P2x3 and/or p2x2/3 compounds and methods

ABSTRACT

The present application provides novel compounds and methods for preparing and using these compounds. In one embodiment, the compounds are of the structure of formula (I), wherein R 1 -R 4  are defined herein. In a further embodiment, these compounds are useful in method for regulating one or both of the P2X 3  or P2X 2/3  receptors. In another embodiment, these compounds are useful for treating pain in patients by administering one or more of the compounds to a patient. In another embodiment, these compounds are useful for treating respiratory dysfunction in patients by administering one or more of the compounds to a patient.

CROSS-REFERENCE TO PRIORITY APPLICATION

The present application is a continuation-in-part of InternationalApplication No. PCT/US2014/070497 filed Dec. 16, 2014, which claims thebenefit of the filing date of U.S. Provisional Application No.61/916,499, filed Dec. 16, 2013, entitled P2X₃ and/or P2X_(2/3)Compounds and Methods, the disclosure of which are hereby incorporatedherein by reference.

BACKGROUND

Adenosine triphosphate (ATP) is well-recognized as the primary energycurrency of living cells, but has also emerged as a significantsignaling molecule that can shape physiological and pathophysiologicalprocesses by interacting with any of several ‘purinergic’membrane-associated receptor molecules. The purinergic receptor familycomprises both G-protein-coupled (GPCR) receptors (assigned a P2Ynomenclature) and ligand-gated ion channel (P2X) variants. ATP elicitsan excitatory effect on afferent sensory nerves via an interaction withreceptors of the P2X subfamily. The consequence of suchhyperexcitability may be interpreted as pain when the ATP effect iselicited in skin, bone or visceral tissues, as pain and/or cough inairway tissues, or as pain and/or instability when it occurs in thebladder. See Ford, Purinergic Signalling, 8 (Suppl 1), S3-S26, 2012;Ford et al., Frontiers in Cellular Neuroscience, Volume 7, Article 267,2013. Two particular receptor variants within the P2X subfamily,designated P2X₃ and P2X_(2/3), have emerged as targets of particularinterest in a variety of studies designed to measure nociception, airwayor bladder function in rodents, since activation of these receptors byATP is capable of generating the adverse events cited above.

Accordingly, there is a need for more potent and selectiveP2X₃/P2X_(2/3) modulators.

SUMMARY OF THE INVENTION

In one aspect, a compound of the structure of formula (I) is provided,wherein R¹-R⁴ are described herein, or a pharmaceutically acceptablesalt thereof.

In another aspect, a compound of the structure of formula (II) isprovided, which is embraced by formula (I), wherein R¹, R², and R⁴ aredescribed herein, or a pharmaceutically acceptable salt thereof.

In a further aspect, a compound of the structure of formula (III) isprovided, which is embraced by formula (I), wherein R¹, R², and R⁴ aredescribed herein, or a pharmaceutically acceptable salt or prodrugthereof.

In yet another aspect, a compound of the structure of formula (IV) isprovided, which is embraced by formula (I), wherein R² and R⁴-R⁶ aredescribed herein, or a pharmaceutically acceptable salt thereof.

In yet another aspect, a compound of the structure of formula (V) isprovided, which is embraced by formula (I), wherein each X isindependently selected from the group consisting of C, CH, CR⁷, N, NH,NR⁷, O and S, and at least one X is N, NH, NR⁷, O or S and at least oneX is C or CR⁷, and R²-R⁴ and R⁷ are described herein, or apharmaceutically acceptable salt thereof.

In yet another aspect, a compound of the structure of formula (VI) isprovided, which is embraced by formula (I), wherein R²-R⁶ are describedherein, or a pharmaceutically acceptable salt thereof.

In still a further aspect, a composition is provided and contains (i) acompound described herein and (ii) a pharmaceutically acceptablecarrier.

In another aspect, a kit is provided and contains a compound describedherein.

In yet a further aspect, a method for regulating activity of one or bothof the P2X₃ or P2X_(2/3) receptors is provided and includesadministering a compound described herein to a patient in need thereof.In one embodiment, the regulation is inhibition.

In a further aspect, a method for modulating one or both of the P2X₃ orP2X_(2/3) pathways is provided and includes administering a compounddescribed herein to the patient. The P2X₃ or P2X_(2/3) pathways canelicit an effect in skin, bone or visceral tissues, airway tissues, orbladder.

In a still further aspect, a method for treating pain in a patient isprovided and includes administering a compound described herein to thepatient.

In yet a further aspect, a method for treating pain, which isnociceptive, dysfunctional, idiopathic, neuropathic, somatic, central,visceral, inflammatory, or procedural, in a patient suffering therefromis provided and includes administering to that patient an amount of acompound described herein which is effective to at least partiallymitigate that pain. In yet a further aspect, the nociceptive paincomprises pain from a cut, bruise, bone fracture, crush injury, burn,trauma, surgery, labor, sprain, bump, injection, dental procedure, skinbiopsy, or obstruction. In yet a further aspect, the dysfunctional paincomprises pain from a rheumatologic condition, tension type headache,irritable bowel disorder or erythermalgia. In yet a further aspect, theneuropathic pain comprises pain due to trauma, surgery, herniation of anintervertebral disk, spinal cord injury, diabetes, infection with herpeszoster, HIV/AIDS, late-stage cancer, amputation, carpal tunnel syndrome,chronic alcohol use, exposure to radiation, or an unintended side-effectof a neurotoxic treatment agent. In yet a further aspect, the somaticpain comprises pain from bone, joint, muscle, skin, or connectivetissue. In yet a further aspect, the central pain comprises pain frombrain trauma, stroke, or spinal cord injury. In yet a further aspect,the visceral pain comprises pain from the respiratory tract,gastrointestinal tract, pancreas, urinary tract or reproductive organs.In yet a further aspect, the inflammatory pain comprises pain due tojoint injury, muscle injury, tendon injury, surgical procedures,infection, or arthritis. In yet a further aspect, the procedural paincomprises pain from medical, dental or surgical procedure. In yet afurther aspect, the procedural pain is postoperative pain, associatedwith an injection, draining an abscess, surgery, dermatological, dentalprocedure, ophthalmic procedure, arthroscopy, or cosmetic surgery.

In yet a further aspect, the pain is caused by airway, bladder orvisceral organ dysfunction. In yet a further aspect, the pain is amigraine, back pain, neck pain, gynecological pain, pre-labor pain,labor pain, orthopedic pain, post-stroke pain, post-surgical pain, postherpetic neuralgia, sickle cell crises, interstitial cystitis,urological pain, dental pain, headache, wound pain, surgical pain,suturing, fracture setting pain, or biopsy. In yet a further aspect, thepain is due to inflammation, nerve compression, or a mechanical forceresulting from tissue distension as a consequence of invasion by a tumorand tumor metastasis into bone or other tissues. In yet a furtheraspect, the pain is caused by esophageal cancer, colitis, cystitis,irritable bowel syndrome, or idiopathic neuropathy. In yet a furtheraspect, the pain is caused by cancer. In yet a further aspect, the painis caused by bone cancer.

In a still further aspect, a method for treating a respiratorydysfunction, sign or symptom in a patient is provided and includesadministering a compound described herein to the patient. Therespiratory dysfunction, sign or symptom includes symptomatic problemssuch as, but not limited to, bronchial hyperactivity,bronchoconstriction, bronchospasm, hypersecretion, cough, coughhypersensitivity syndrome, wheezing, dyspnea, breathless, and chesttightness.

In yet a further aspect, a method for treating cough, including chroniccough, pathologic cough, and the urge to cough, or related respiratorysymptoms such as wheezing, bronchospasm, dyspnea and chest-tightness dueto a respiratory disease or disorder, in a patient suffering therefromis provided. The respiratory disease or disorder includes conditionswhere the subject experiences cough hypersensitivity, such as idiopathicpulmonary fibrosis (IPF), chronic obstructive pulmonary disease (COPD),asthma, upper respiratory infection, interstitial lung disease (ILD),post-nasal drip, and bronchitis. The cough may be sub-acute or chronic.The cough may be associated with gastroesophageal reflux disease (GERD).The cough may be an iatrogenic cough, including cough associated withtreatment with an ACE (Angiotensin Converting Enzyme) inhibitor. Thecough may be “smoker's cough”, that is, cough associated with smoking.The method includes administering to that patient an amount of acompound described herein which is effective to at least partiallymitigate that condition.

Other aspects and advantages of the invention will be readily apparentfrom the following detailed description of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a map of a circular cloning plasmid pIRESpuro3 (ClontechLaboratories Inc., Mountain View, Calif.) into which the protein codingsequence of rat P2X2 has been cloned in the EcoRV-digested anddephosphorylated vector pIRES-puro3 within a multiple cloning site(MCS).

FIG. 1B is a map of a circular plasmid pCDNA-Hygro (Invitrogen) intowhich the coding sequence of rat P2X3 (NCBI Accession No: X91167),amplified by PCR from rat brain cDNA, has been cloned. The PCR productobtained containing the protein coding sequence of rat P2X3 was clonedinto EcoRV-digested and dephosphorylated vector pCDNA-Hygro within themultiple cloning site (MCS).

FIG. 1C is a vector generated from the pcDNA-Hygro containing the ratP2X3, which was then subcloned into pcDNA-5/TO (Invitrogen/LifeTechnologies) at HindIII (5′) and XhoI (3′) sites within the multiplecloning site (MCS) of the vector.

FIG. 2 illustrates the antihyperalgesic effects of the compound ofexample 22 in a rat model of inflammatory thermal hyperalgesia inducedby an intraplantar injection of Complete Freund's Adjuvant (CFA).Thermal hyperalgesia is manifest as a reduction in the time forfoot-withdrawal during irradiation with a painful thermal stimulus. Thecompound of example 22 was administered at a dose of 60 mg/kg, 48 hafter footpad injection of CFA and produced a substantial reversal (77%and 68%) of thermal hyperalgesia when assessed at 1 h and 2 h post-dose,respectively.

FIG. 3 illustrates the antinociceptive effects of the compound ofexample 22 in a rat model of ongoing spontaneous pain. The compound ofexample 22 was administered by oral gavage at a dose of 100 mg/kgfollowed 30 min later by a footpad injection of a dilute formalinsolution. Formalin elicits a typical biphasic nociceptive response thatmanifests as spontaneous hind limb flinches which are counted and binnedover 5 min epochs. The compound of example 22 attenuated the secondphase flinching response to formalin a profile that is consistent withan antinociceptive action.

FIG. 4 illustrates the antinociceptive effects of the compound ofexample 22 in a mouse model of visceral pain. The compound of example 22was administered by oral gavage at 3 dose levels (20, 40 and 60 mg/kg)30 min prior to an intraperitoneal injection of a dilute acetic acidsolution. When injected into the abdominal cavity, acetic acid induces adistinctive stretching response in the abdomen and at least one hindlimb that is assumed to reflect a response to visceral pain. Thecompound of example 22 produced a clear dose-related reduction in thepain responses when assessed for a total of 15 min post acetic acidinjection. Statistical significance is indicated with respect to thevehicle control group and was performed using a one-way ANOVA followedby Dunnett's multiple comparison test.

FIG. 5 illustrates the antihyperalgesic effects of the compound ofexample 38 in a rat model of inflammatory thermal hyperalgesia inducedby an intraplantar injection of CFA. Thermal hyperalgesia is manifest asa reduction in the time for foot-withdrawal during irradiation with apainful thermal stimulus. The compound of example 38 was administered ata dose of 60 mg/kg, 48 h after footpad injection of CFA and produced asubstantial reversal (50%) of thermal hyperalgesia when assessed at 1 hpost-dose.

FIG. 6 illustrates the antihyperalgesic effects of the compound ofexample 52 in a rat model of inflammatory thermal hyperalgesia inducedby an intraplantar injection of CFA. Thermal hyperalgesia is manifest asa reduction in the time for foot-withdrawal during irradiation with apainful thermal stimulus. The compound of example 52 was administered ata dose of 60 mg/kg, 48 h after footpad injection of CFA and produced asubstantial reversal (39%) of thermal hyperalgesia when assessed at 1 hpost-dose.

DETAILED DESCRIPTION OF THE INVENTION

Discussed herein are novel compounds which have capabilities inmodulating one or both of the P2X₃ or P2X_(2/3) pathways. Thesecompounds may be used to treat disease affected by a dysregulation ofone or both of the P2X₃ or P2X_(2/3) pathways.

The compounds discussed herein have the structure of formula (I).

In this structure, R¹ is unsubstituted or substituted heteroaryl orNR⁵R⁶. In one aspect, R¹ is unsubstituted or substituted heteroaryl. Inanother embodiment, R¹ is heteroaryl containing one to four heteroatomsor heterogroups selected from —O—, —N—, —S—, —S(═O)—, —S(═O)₂, or—C(═O)—, which is unsubstituted or substituted with one or more halogen,C₁ to C₆ alkyl, C₃ to C₆ cycloalkyl, C₃ to C₆ cycloalkyl-C₁ to C₆ alkyl,C₁ to C₆ hydroxyalkyl, C₁ to C₆ alkoxy, C₁ to C₆ alkyl containing 1 to 3fluorine atoms, or CH₂CONH₂. In another embodiment, R¹ is a 5-memberedheteroaryl containing one to four heteroatoms selected from —O—, —N—, or—S—, which is unsubstituted or substituted with one or more halogen, C₁to C₆ alkyl, C₃ to C₆ cycloalkyl, C₃ to C₆ cycloalkyl-C₁ to C₆ alkyl, C₁to C₆ hydroxyalkyl, C₁ to C₆ alkoxy, C₁ to C₆ alkyl containing 1 to 3fluorine atoms, or CH₂CONH₂. Non-limiting examples of 5-memberedheteroaryl rings include, but not limited to, oxadiazole, pyrazole,thiophene, isoxazole, imidazole, tetrazole, triazole, furan, pyrrole,thiazole, isothiazole, or thiadiazole. In one embodiment, each of these5-membered heteroaryl may be substituted with one or more halogen, C₁ toC₆ alkyl, C₃ to C₆ cycloalkyl, C₃ to C₆ cycloalkyl-C₁ to C₆ alkyl, C₁ toC₆ hydroxyalkyl, C₁ to C₆ alkoxy, C₁ to C₆ alkyl containing 1 to 3fluorine atoms, or CH₂CONH₂. In yet another embodiment, R¹ is oxadiazolesubstituted with one or more C₁ to C₆ alkyl, pyrazole substituted withone or more C₁ to C₆ alkyl, pyrazole substituted with one or more C₃ toC₆ cycloalkyl-C₁ to C₆ alkyl, pyrazole substituted with one or more C₁to C₆ alkyl containing 1 to 3 fluorine atoms, pyrazole substituted withone or more CH₂CONH₂ groups, thiophene substituted with one or more C₁to C₆ alkyl, or isoxazole substituted with one or more C₁ to C₆ alkyl.In still a further embodiment, R¹ is oxadiazole substituted with one C₁to C₆ alkyl, pyrazole substituted with one C₁ to C₆ alkyl, pyrazolesubstituted with one C₃ to C₆ cycloalkyl-C₁ to C₆ alkyl, pyrazolesubstituted with one C₁ to C₆ alkyl containing 1 fluorine atom, pyrazolesubstituted with one or more CH₂CONH₂ group, thiophene substituted withone C₁ to C₆ alkyl, or isoxazole substituted with one or two C₁ to C₆alkyl. In another embodiment, R¹ is oxadiazole substituted with oneethyl, pyrazole substituted with one CH₃ or CH₂CH₃, pyrazole substitutedwith one —CH₂-cyclopropyl, pyrazole substituted with one CH₂CH₂F,pyrazole substituted with one or more CH₂CONH₂ group, thiophenesubstituted with one CH₃, or isoxazole substituted with two CH₃. In yetanother embodiment, R¹ is 2-ethyl-1,3,4-oxadiazole, 1-methyl-pyrazole,1-ethyl-pyrazole, 1-cyclopropylmethane-pyrazole,1-fluoroethane-pyrazole, 1-carboxamidomethyl-pyrazole,2-methyl-thiophene, or 3,5-dimethyl-isoxazole. In another embodiment, R¹is imidazole substituted with one or more C₁ to C₆ alkyl. In yet anotherembodiment, R¹ is tetrazole substituted with one or more C₃ to C₆cycloalkyl, C₁ to C₆ alkyl, C₁ to C₆ hydroxyalkyl, C₁ to C₆ alkylcontaining 1-3 fluorine atoms, and C₃ to C₆ cycloalkyl-C₁ to C₆ alkyl.In a further embodiment, R¹ is triazole substituted with one or more C₃to C₆ cycloalkyl, C₁ to C₆ alkyl containing 1-3 fluorine atoms, and C₁to C₆ alkyl. In a further embodiment, R¹ is 2,5-dimethyl-imidazole,5-ethyl-pyrazole, 5-propyl-tetrazole, 5-cyclopropyl-tetrazole,5-propyl-tetrazole, 5-isopropyl-tetrazole, 5-ethyl-tetrazole,5-cyclobutyl-tetrazole, 5-cyclopropylmethyl-tetrazole,5-methyl-tetrazole, 5-hydroxymethyl-tetrazole,5-difluoromethyl-tetrazole, 5-(2,2,2-trifluoroethyl)-tetrazole,5-(1,1-difluoroethyl)-tetrazole, 5-cyclopropyl-triazole,5-difluoromethyl-triazole, 5-trifluoromethyl-triazole,5-methyl-triazole, 5-isopropyl-triazole, 5-propyl-triazole,5-ethyl-triazole, 5-tert-butyl-triazole, 5-cyclobutyl-triazole,5-(1,1-difluoroethyl)-triazole, 5-(2,2,2-trifluoroethyl)-triazole, or3,5-dimethyl-1,2,4-triazole.

In another aspect, R¹ is NR⁵R⁶. In one embodiment, R⁵ and R⁶ are,independently, chosen from H, unsubstituted or substituted C₁ to C₆alkyl, C₃ or C₆ cycloalkyl, unsubstituted or substituted aryl,unsubstituted or substituted heteroaryl, and CO(C₁ to C₆ alkyl). In afurther embodiment, R⁵ and R⁶ are unsubstituted or substituted phenyl.In another embodiment, R⁵ and R⁶ are phenyl substituted with fluorine orC₁ to C₆ alkoxy. In yet a further embodiment, one or both of R⁵ and R⁶are unsubstituted or substituted thiazole. In still another embodiment,one or both of R⁵ and R⁶ are unsubstituted or substituted C₁ to C₆ alkylor C₃ to C₆ cycloalkyl. In a further embodiment, one or both of R⁵ andR⁶ are 4-fluoro-phenyl or 2-methoxy-phenyl. In another embodiment, R⁵and R⁶ are joined to form a 5 or 6-membered heterocyclic ringunsubstituted or substituted by one or more of halogen, C₁ to C₆ alkyl,C₁ to C₆ alkoxy, C₁ to C₆ hydroxyalkyl, C₃ to C₆ cycloalkyl, C₃ to C₆cycloalkyl-C₁ to C₆ alkyl, C₁ to C₆ alkyl containing 1 to 3 fluorineatoms, or CONH₂. In still a further embodiment, R⁵ and R⁶ are joined toform an unsubstituted or substituted 5 or 6-membered heterocyclic ring.In yet another embodiment, R⁵ and R⁶ are joined to form an unsubstitutedor substituted pyrrolidine, piperidine, or piperazine. In a furtherembodiment, R⁵ and R⁶ are joined to form pyrrolidine unsubstituted orsubstituted with one or more C₁ to C₆ alkyl or C₁ to C₆ alkoxy. Inanother embodiment, R⁵ and R⁶ are joined to form piperidine substitutedwith one or more C₁ to C₆ alkoxy, halogen, C₁ to C₆ alkyl containing 1-3fluorine atoms, C₁ to C₆ alkyl, or CONH₂. In yet another embodiment, R⁵and R⁶ are joined to form piperazine substituted with CONH₂. In still afurther embodiment, R⁵ and R⁶ are joined to form 3-methoxy-pyrrolidine,3-methyl-3-methoxy-pyrrolidine, 4-methyl-piperidine,4,4-dimethyl-piperidine, 4,4-difluoro-piperidine,4-methyl-4-carboxamido-piperidine, 4-fluoro-piperidine,4-trifluoromethyl-piperidine, 4-fluoromethyl-piperidine,4-methyl-4-methoxy-piperidine, 4-methoxy-piperidine,3-methoxy-piperidine, or 4-carboxamido-piperazine.

R² is unsubstituted or substituted aryl, unsubstituted or substitutedheteroaryl, C₁ to C₆ alkyl, or S—C₁ to C₆ alkyl. In one embodiment, R²is unsubstituted or substituted aryl. In another embodiment, R² isunsubstituted or substituted phenyl. In a further embodiment, R² isphenyl substituted with one or more C₁ to C₆ alkyl. In yet anotherembodiment, R² is phenyl substituted with one CH₃. In still anotherembodiment, R² is 2-tolyl or 3-tolyl. In a further embodiment, R² is C₁to C₆ alkyl. In another embodiment, R² is butyl. In still a furtherembodiment, R² is —S—(C₁ to C₆ alkyl). In yet another embodiment, R² isSCH₂CH₂CH₃. In a further embodiment, R² is unsubstituted or substitutedheteroaryl. In still another embodiment, R² is heteroaryl substitutedwith one or more halogen, cyano, C₁ to C₆ alkyl or C₁ to C₆ alkylcontaining 1-3 fluorine atoms. In yet a further embodiment, R² isthiazole, thiophene, or furan. In another embodiment, R² is thiazolesubstituted with C₁ to C₆ alkyl. In still a further embodiment, R² isthiophene substituted with one or more of halogen, cyano, C₁ to C₆ alkylor C₁ to C₆ alkyl containing 1-3 fluorine atoms. In yet anotherembodiment, R² is furan substituted with C₁ to C₆ alkyl. In a furtherembodiment, R² is 2-chloro-thiophene, 2-methyl-thiophene,2-cyano-thiophene, 2-trifluoromethyl-thiophene, 5-methyl-thiazole,2-methyl-thiazole, or 2-methyl-furan.

R³ is H or C₁ to C₆ alkyl. In one embodiment, R³ is H. In anotherembodiment, R³ is C₁ to C₆ alkyl.

R⁴ is unsubstituted or substituted heteroaryl. In one embodiment, R⁴ isunsubstituted or substituted triazole, unsubstituted or substitutedpyridine, unsubstituted or substituted pyridone, unsubstituted orsubstituted oxadiazole, unsubstituted or substituted pyrazine, orunsubstituted or substituted pyrimidine. In another embodiment, R⁴ isheteroaryl unsubstituted or substituted with C₁ to C₆ alkyl, C₃ to C₆cycloalkyl, C₁ to C₆ alkoxy, or C₁ to C₆ trifluoroalkyl. In a furtherembodiment, R⁴ is pyridine substituted with one or more C₁ to C₆ alkyl,C₃ to C₆ cycloalkyl, C₁ to C₆ alkoxy, or C₁ to C₆ trifluoroalkyl. In yetanother embodiment, R⁴ is pyridine and the nitrogen atom of saidpyridine is bound to an O-atom. In still a further embodiment, R⁴ ispyrazine substituted with one or more C₁ to C₆ alkyl. In anotherembodiment, R⁴ is pyrimidine substituted with one or more C₁ to C₆ alkylor C₁ to C₆ alkoxy. In yet a further embodiment, R⁴ is pyridonesubstituted with one or more C₁ to C₆ alkyl. In still anotherembodiment, R⁴ is 1,2,4-triazole, 2-methyl-pyridine, 2-methoxy-pyridine,1-oxo-pyridine, 1-oxo-2-methyl-pyridine,1-oxo-2-trifluoromethyl-pyridine, 2-trifluoromethyl-pyridine,2-cyclopropyl-pyridine, 1,3,4-oxadiazole, 1,2,4-oxadiazole,3-methyl-1,2,4-oxadiazole, 2-methyl-1,3,4-oxadiazole, 2-methyl-pyrazine,2-methyl-pyrimidine, 2-methoxy-pyrimidine, or 1-methyl-pyridone.

In one embodiment, the compounds are of the structure of formula (II),wherein R¹, R², and R⁴ are defined above.

In another embodiment, the compounds are of the structure of formula(III), wherein R¹, R², and R⁴ are defined above.

In a further embodiment, the compounds are of the structure of formula(IV), wherein R² and R⁴-R⁶ are defined above.

In a further embodiment, the compounds are of the structure of formula(V), wherein each X is independently selected from the group consistingof C, CH, CR⁷, N, NH, NR⁷, O and S, and at least one X is N, NH, NR⁷, Oor S and at least one X is C or CR⁷, and R²-R⁴ are defined above, and R⁷is halogen, C₁ to C₆ alkyl, C₃ to C₆ cycloalkyl, C₃ to C₆ cycloalkyl-C₁to C₆ alkyl, C₁ to C₆ hydroxyalkyl, C₁ to C₆ alkoxy, C₁ to C₆ alkylcontaining 1 to 3 fluorine atoms, or CH₂CONH₂.

In a further embodiment, the compounds are of the structure of formula(VI), wherein R²-R⁶ are defined above.

Representative “pharmaceutically acceptable salts” include but are notlimited to those of an acid or base. In one embodiment, thepharmaceutical salt is selected from among water-soluble andwater-insoluble salts. The salt may be of an acid selected from, e.g.,among acetic, propionic, lactic, citric, tartaric, succinic, fumaric,maleic, malonic, mandelic, malic, phthalic, hydrochloric, hydrobromic,phosphoric, nitric, sulfuric, methanesulfonic, napthalenesulfonic,benzenesulfonic, toluenesulfonic, trifluoroacetic, and camphorsulfonic.The salt can also be of a base selected from, e.g., sodium, potassium,calcium, and ammonium. In some embodiments, a composition of theinvention may contain both a pharmaceutically acceptable salt and thefree base form of a compound of the invention.

A compound of the invention may also be a prodrug of formulae (I-VI).Prodrugs of compounds of formulae (I-VI) may be prepared using variousmethods known to those skilled in the art. See, e.g., Rautio, NatureReviews Drug Discovery, 7:255-270 (2008) and Ettmayer, J. Med. Chem.,47:2393-2404 (2004), which are hereby incorporated by reference. In thecase of drugs containing a hydroxy moiety, acetyl and other esteranalogs are contemplated for use as prodrugs. See, e.g., Beaumont,Current Drug Metabolism, 4:461-485 (2003), which is hereby incorporatedby reference. In the case of drugs containing an amine moiety, prodrugscontaining amides and carbamates are contemplated. See, e.g., Simplicio,Molecules, 13:519-547 (2008), which is hereby incorporated by reference.As specific examples, (alkoxycarbonyloxy)alkyl carbamates,(acyloxy)alkyl carbamates, and (oxodioxolenyl)alkyl carbamates may beutilized as effective prodrug strategies for amines See, e.g., Li,Bioorg. Med. Chem. Lett., 7:2909-2912 (1997); Alexander, J. Med. Chem.,34:78-81 (1991); Alexander, J. Med. Chem., 31:318-322 (1988); andAlexander, J. Med. Chem., 39:480-486 (1996), all of which areincorporated by reference herein.

Some compounds described herein possess one or more chiral centers.Therefore, the disclosure of each compound includes its separateenantiomers as well as mixtures of the enantiomers. Where multiplechiral centers exist in the compounds, also provided are each possiblecombination of chiral centers within a compound, as well as all possibleenantiomeric and diastereomeric mixtures thereof. All chiral,diastereomeric, and racemic forms of a structure are intended, unlessthe specific stereochemistry or isomeric form is specifically indicated.It is well known in the art how to prepare optically active forms, suchas by resolution of racemic forms or by synthesis from optically activestarting materials.

The following definitions are used in connection with the compoundsdescribed herein. In general, the number of carbon atoms present in agiven group is designated “C_(x) to C_(y)”, where x and y are the lowerand upper limits, respectively. The carbon number as used in thedefinitions herein refers to carbon backbone and carbon branching, butdoes not include carbon atoms of the substituents, such as alkoxysubstitutions and the like. Unless indicated otherwise, the nomenclatureof substituents that are not explicitly defined herein is determined bynaming from left to right the terminal portion of the functionalityfollowed by the adjacent functionality toward the point of attachment.As used herein, “unsubstituted or substituted” means that at least 1hydrogen atom of the optionally substituted group has been replaced.

“Alkyl” refers to a hydrocarbon chain that may be straight or branched.In one embodiment, an alkyl contains 1 to 6 (inclusive) carbon atoms. Inanother embodiment, an alkyl contains 1 to 5 (inclusive) carbon atoms.In a further embodiment, an alkyl contains 1 to 4 (inclusive) carbonatoms. In yet another embodiment, an alkyl contains 1 to 3 (inclusive)carbon atoms. In still a further embodiment, an alkyl contains 1 or 2carbon atoms. Examples of alkyl groups that are hydrocarbon chainsinclude, but are not limited to, methyl, ethyl, propyl, butyl, pentyl,and hexyl, where all isomers of these examples are contemplated.

Alkyl groups may also consist of or contain a cyclic alkyl radical,i.e., “carbocyclic ring” or “cycloalkyl”. Examples of carbocyclic ringsinclude, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl, and the like. In one embodiment, the carbocyclic ring is 3-to 6-membered. In another embodiment, the carbocyclic ring is a 3- to5-membered ring. In a further embodiment, the carbocyclic ring is 4- to6-membered. In still a further embodiment, the carbocyclic ring is 3- or4-membered, i.e., cyclopropyl or cyclobutyl. Unless specifically noted,the alkyl groups are unsubstituted, i.e., they contain carbon andhydrogen atoms only. However, when the alkyl group or carbocyclic ringis substituted, it is prefaced with the term “unsubstituted orsubstituted” or “substituted”. The optional substituents of the alkylgroups or carbocyclic rings include, without limitation, halogen, CN,NO₂, C₁ to C₆ alkyl, OH, C₁ to C₆ alkoxy, C₁ to C₆ alkoxy-C₁ to C₆alkoxy, C₁ to C₆ alkoxy-C₁ to C₆ alkyl-C₁ to C₆ alkoxy, heterocyclyloxy,C₁ to C₆ alkylthio, aryl, heterocycle, heteroaryl, C(O)(C₁ to C₆ alkyl),C(O)(heterocycle), C(O)O(C₁ to C₆ alkyl), C(O)NH₂, C(O)NH(C₁ to C₆alkyl), C(O)N(C₁ to C₆ alkyl)(C₁ to C₆ alkyl), SO₂(C₁ to C₆ alkyl),SO₂(C₂ to C₆ alkynyl), SO₂NH(C₁ to C₆ alkyl), SO₂(heterocycle),NHC(O)(C₁ to C₆ alkyl), NHSO₂(C₁ to C₆ alkyl), N(C₁ to C₆ alkyl)SO₂(C₁to C₆ alkyl), NH₂, NH(aryl), N(C₁ to C₆ alkyl)(C₁ to C₆ alkyl), andNHC(O)NH₂.

“Alkoxy” refers to

O(alkyl), where the alkyl is unsubstituted or substituted and is definedabove. In one embodiment, an alkoxy contains 1 to 6 (inclusive) carbonatoms or integers or ranges there between. In another embodiment, analkoxy contains 1 to 5 (inclusive) carbon atoms or ranges therebetween.In a further embodiment, an alkoxy contains 1 to 4 (inclusive) carbonatoms. In still a further embodiment, an alkoxy contains 1 to 3(inclusive) carbon atoms. In still a further embodiment, an alkoxycontains 1 or 2 carbon atoms. Examples of alkoxy include, but are notlimited to, methoxy, ethoxy, propoxy, and butoxy. The alkyl radical ofan alkoxy group can be unsubstituted or substituted as defined above for“alkyl”.

“Aryl” refers to an aromatic hydrocarbon group containing carbon atoms.In one embodiment, the aryl contains 6 to 10 carbon atoms, i.e., 6-, 7-,8-, 9- or 10-membered. In another embodiment, aryl is an aromatic orpartly aromatic bicyclic group. In a further embodiment, the aryl is aphenyl group. In another embodiment, the aryl is naphthyl (such asα-naphthyl or β-naphthyl), 1,2,3,4-tetrahydronaphthyl, or indanyl. Anaryl group can be unsubstituted or substituted with one or more groupsincluding, without limitation, halogen, NO₂, C₁ to C₆ alkyl, OH, C₁ toC₆ alkoxy, C₁ to C₆ alkoxy-C₁ to C₆ alkoxy, C₁ to C₆ alkoxy-C₁ to C₆alkoxy-C₁ to C₆ alkoxy, heterocyclyloxy, C₁ to C₆ alkylthio, aryl,heterocycle, heteroaryl, C(O)(C₁ to C₆ alkyl), C(O)(heterocycle),C(O)O(C₁ to C₆ alkyl), C(O)NH₂, C(O)NH(C₁ to C₆ alkyl), C(O)N(C₁ to C₆alkyl)(C₁ to C₆ alkyl), SO₂(C₁ to C₆ alkyl), SO₂(C₂ to C₆ alkynyl),SO₂NH(C₁ to C₆ alkyl), SO₂(heterocycle), NHSO₂(C₁ to C₆ alkyl), N(C₁ toC₆ alkyl)SO₂(C₁ to C₆ alkyl), NH₂, NH(aryl) or NHC(O)NH₂.

“Halogen” refers to F, Cl, Br and I.

The term “heteroatom” refers to a sulfur, nitrogen, or oxygen atom.“Heteroaryl” refers to a monocyclic aromatic 5- or 6-membered ringcontaining one to four heteroatoms or heterogroups selected from —O—,—N—, —S—, —S(═O)—, —S(═O)₂, or —C(═O)—. In one embodiment, theheteroaryl contains 1 to 5 carbon atoms (inclusive) or integers orranges therebetween. In another embodiment, the heteroaryl contains 2 to5 carbon atoms (inclusive). In a further embodiment, the heteroarylcontains 3 to 5 carbon atoms (inclusive). In still a further embodiment,the heteroaryl contains 4 or 5 carbon atoms. “Heteroaryl” also refers tobicyclic aromatic ring systems wherein a heteroaryl group as justdescribed is fused to at least one other cyclic moiety. In oneembodiment, a phenyl radical is fused to a 5- or 6-membered monocyclicheteroaryl to form the bicyclic heteroaryl. In another embodiment, acyclic alkyl is fused to a monocyclic heteroaryl to form the bicyclicheteroaryl. In a further embodiment, the bicyclic heteroaryl is apyridine fused to a 5- or 6-membered monocyclic heteroaryl. In still afurther embodiment, the heteroaryl ring has 1 or 2 nitrogen atoms in thering. In still a further embodiment, the heteroaryl ring has 1 nitrogenatom and 1 oxygen atom. In still a further embodiment, the heteroarylring has 1 nitrogen atom and 1 sulfur atom. Examples of heteroarylgroups include, without limitation, furan, thiophene, indole, azaindole,oxazole, thiazole, isoxazole, isothiazole, imidazole, pyridine,pyridone, pyrazole, pyrimidine, pyrazine, pyridazine, pyrrole,oxadiazole such as 1,3,4-oxadiazole, triazole such as 1,2,4-triazole,tetrazole, benzoxazole, benzothiazole, benzofuran, benzisoxazole,benzimidazole, azabenzimidazole, indazole, quinazoline, quinoline, andisoquinoline. A heteroaryl may be unsubstituted or substituted with oneor more groups including, without limitation, halogen, CN, NO₂, C₁ to C₆alkyl, OH, C₁ to C₆ alkoxy, C₃ to C₈ cycloalkyl, C₁ to C₆ alkoxy-C₁ toC₆ alkoxy, C₁ to C₆ alkoxy-C₁ to C₆ alkoxy-C₁ to C₆ alkoxy, C₁ or C₆alkyl containing 1 to 3 fluorine atoms, C₁ to C₆ alkoxy containing 1 to3 fluorine atoms, C₃ to C₆ cycloalkyl-C₁ to C₆ alkyl, C₁ to C₆hydroxyalkyl, heterocyclyloxy, C₁ to C₆ alkylthio, aryl, heterocycle,heteroaryl, C(O)(C₁ to C₆ alkyl), C(O)(heterocycle), C(O)O(C₁ to C₆alkyl), C(O)NH₂, C(O)NH(C₁ to C₆ alkyl), C(O)N(C₁ to C₆ alkyl)(C₁ to C₆alkyl), SO₂(C₁ to C₆ alkyl), SO₂(C₂ to C₆ alkynyl), SO₂NH(C₁ to C₆alkyl), SO₂(heterocycle), NHC(O)(C₁ to C₆ alkyl), NHSO₂(C₁ to C₆ alkyl),N(C₁ to C₆ alkyl)SO₂(C₁ to C₆ alkyl), NH₂, NH(aryl), N(C₁ to C₆alkyl)(C₁ to C₆ alkyl) and NHC(O)NH₂. In one embodiment, “heteroaryl”refers to 5-membered heteroaryl containing one to four heteroatomsselected from —O—, —N—, or —S—, which is unsubstituted or substitutedwith one or more halogen, C₁ to C₆ alkyl, C₃ to C₆ cycloalkyl, C₃ to C₆cycloalkyl-C₁ to C₆ alkyl, C₁ to C₆ hydroxyalkyl, C₁ to C₆ alkoxy, C₁ toC₆ alkyl containing 1 to 3 fluorine atoms, or CH₂CONH₂. Non-limitingexamples of 5-membered heteroaryl rings include, but not limited to,oxadiazole, pyrazole, thiophene, isoxazole, imidazole, tetrazole,triazole, furan, pyrrole, thiazole, isothiazole, or thiadiazole. Each ofthese 5-membered heteroaryl may be substituted with one or more halogen,C₁ to C₆ alkyl, C₃ to C₆ cycloalkyl, C₃ to C₆ cycloalkyl-C₁ to C₆ alkyl,C₁ to C₆ hydroxyalkyl, C₁ to C₆ alkoxy, C₁ to C₆ alkyl containing 1 to 3fluorine atoms, or CH₂CONH₂.

“Heterocycle” refers to a monocyclic or bicyclic group having one tothree heteroatoms or heterogroups selected from —O—, —N—, —S—, —S(═O)—,—S(═O)₂, or —C(═O)—. A heterocycle may be saturated or partiallysaturated. In one embodiment, the heterocycle contains 3 to 7 carbonatoms (inclusive) or integers or ranges therebetween. In anotherembodiment, the heterocycle contains 4 to 7 carbon atoms (inclusive). Ina further embodiment, the heterocycle contains 4 to 6 carbon atoms(inclusive). In still a further embodiment, the heterocycle contains 5or 6 carbon atoms (inclusive). Examples of heterocycles include, but arenot limited, to aziridine, oxirane, thiirane, morpholine,thiomorpholine, pyrroline, pyrrolidine, azepane, dihydrofuran,tetrahydrofuran, dihydrothiophene, tetrahydrothiophene, dithiolane,piperidine, 1,2,3,6-tetrahydropyridine-1-yl, tetrahydropyran, pyran,thiane, thiine, piperazine, homopiperazine, oxazine, azecane,tetrahydroquinoline, perhydroisoquinoline,5,6-dihydro-4H-1,3-oxazin-2-yl, 2,5-diazabicyclo[2.2.1]heptane,2,5-diazabicyclo[2.2.2]octane, 3,6-diazabicyclo[3.1.1]heptane,3,8-diazabicyclo[3.2.1]octane, 6-oxa-3,8-diazabicyclo[3.2.1]octane,7-oxa-2,5-diazabicyclo[2.2.2]octane,2,7-dioxa-5-azabicyclo[2.2.2]octane,2-oxa-5-azabicyclo[2.2.1]heptane-5-yl, 2-oxa-5-azabicyclo[2.2.2]octane,3,6-dioxa-8-azabicyclo[3.2.1]octane, 3-oxa-6-azabicyclo[3.1.1]heptane,3-oxa-8-azabicyclo[3.2.1]octan-8-yl,5,7-dioxa-2-azabicyclo[2.2.2]octane,6,8-dioxa-3-azabicyclo[3.2.1]octane, 6-oxa-3-azabicyclo[3.1.1]heptane,8-oxa-3-azabicyclo[3.2.1]octan-3-yl,2,5-diazabicyclo[2.2.1]heptane-5-yl, 6-azabicyclo[3.2.1]oct-6-yl,8-azabicyclo[3.2.1]octan-8-yl, 3-oxa-7,9-diazabicyclo[3.3.1]nonan-9-yl,9-oxa-3-azabicyclo[3.3.1]nonan-3-yl,3-oxa-9-azabicyclo[3.3.1]nonan-9-yl,3,7-dioxa-9-azabicyclo[3.3.1]nonan-9-yl,3,4-dihydro-2H-1,4-benzoxazin-7-yl, thiazine, dithiane, and dioxane. Inanother embodiment, the heterocycle contains 1 or 2 nitrogen atoms. In afurther embodiment, the heterocycle contains 1 or 2 nitrogen atoms and 3to 6 carbon atoms. In still a further embodiment, the heterocyclecontains 1 or 2 nitrogen atoms, 3 to 6 carbon atoms, and 1 oxygen atom.In a still a further embodiment, the heterocycle is 5- to 8-membered. Instill a further embodiment, the heterocycle is 5-membered. In still afurther embodiment, the heterocycle is 6-membered. In still a furtherembodiment, the heterocycle is 8-membered. A heterocycle may beunsubstituted or substituted with one or more groups including, withoutlimitation, halogen, CN, NO₂, C₁ to C₆ alkyl, OH, C₁ to C₆ alkoxy, C₁ toC₆ alkoxy-C₁ to C₆ alkoxy, C₁ to C₆ alkoxy-C₁ to C₆ alkoxy-C₁ to C₆alkoxy, C₁ to C₆ hydroxyalkyl, C₃ to C₆ cycloalkyl, C₁ to C₆ alkylcontaining 1 to 3 fluorine atoms, C₃ to C₆ cycloalkyl-C₁ to C₆ alkyl,heterocyclyloxy, C₁ to C₆ alkylthio, aryl, heterocycle, heteroaryl,C(O)(C₁ to C₆ alkyl), C(O)(heterocycle), C(O)O(C₁ to C₆ alkyl), C(O)NH₂,C(O)NH(C₁ to C₆ alkyl), C(O)N(C₁ to C₆ alkyl)(C₁ to C₆ alkyl), SO₂(C₁ toC₆ alkyl), SO₂(C₂ to C₆ alkynyl), SO₂NH(C₁ to C₆ alkyl),SO₂(heterocycle), NHC(O)(C₁ to C₆ alkyl), NHSO₂(C₁ to C₆ alkyl), N(C₁ toC₆ alkyl)SO₂(C₁ to C₆ alkyl), NH₂, NH(aryl), N(C₁ to C₆ alkyl)(C₁ to C₆alkyl) and NHC(O)NH₂.

“Alkylamino” refers to an NH or N group, the nitrogen atom of the groupbeing attached to 1 or 2 alkyl substituents, respectively, wherein thealkyl is unsubstituted or substituted and defined above. The alkylaminois bound through the nitrogen atom of the group. In one embodiment,alkylamino refers to

NH(alkyl). In another embodiment, alkylamino refers to

N(alkyl)(alkyl), i.e., a “dialkylamino” In a further embodiment,alkylamino refers to

N(C₁ to C₆ alkyl)(C₁ to C₆ alkyl). In still a further embodiment,alkylamino refers to

N(alkyl)(heterocycle). In still a further embodiment, alkylamino refersto

N(alkyl)(aryl). In still a further embodiment, alkylamino refers to

N(alkyl)(heteroaryl). In still a further embodiment, alkylamino refersto

N(alkyl)(alkenyl). When the nitrogen atom is bound to two alkyl groups,each alkyl group may be independently selected. In still a furtherembodiment, two alkyl groups on the nitrogen atom may be taken togetherwith the nitrogen to which they are attached to form a 3- to 4-memberednitrogen-containing heterocycle where up to two of the carbon atoms ofthe heterocycle can be replaced with N(H), N(C₁ to C₆ alkyl), N(aryl),N(heteroaryl), O, S(O), or S(O)₂. Examples of alkylamino include, butare not limited to N(CH₃)₂, N(CH₂CH₃)(CH₃), N(CH₂CH₃)₂, N(CH₂CH₂CH₃)₂,N(CH₂CH₂CH₂CH₃)₂, and N(CH(CH₃)₂)(CH₃).

“Acylamino” refers to an NH or N group, the nitrogen atom of the groupbeing attached to 1 or 2 aryl substituents, respectively, wherein thearyl is unsubstituted or substituted and defined above. The arylamino isbound through the nitrogen atom of the group. In one embodiment,arylamino refers to

NH(aryl). In another embodiment, arylamino refers to

N(aryl)(aryl), i.e., a “diarylamino” When the nitrogen atom is bound totwo aryl groups, each aryl may be independently selected.

“Alkylcarbonylamino” refers to

NHC(O)(alkyl) or

N(alkyl)C(O)(alkyl) where the alkyl groups are independently defined andindependently unsubstituted or substituted as described above. Examplesof alkylcarbonylamino include, but are not limited to, CH₃CONH,CH₃CH₂CONH, CH₃CH₂CH₂CONH, and CH₃CH(CH₃)CONH.

“Ester” refers to

C(O)O(alkyl), which is bound through the carbon atom. The alkyl group isdefined and unsubstituted or substituted as described above. Examples ofester include, without limitation, C(O)OCH₃, C(O)O(CH₂CH₃),C(O)O(CH₂CH₂CH₃), and C(O)(0)(CH₂CH₂CH₂CH₃).

“Urea” refers to a group having a

NHC(O)NH

where one of the nitrogen atoms is bound to an alkyl or heteroarylgroup. The alkyl or heteroaryl groups are defined and unsubstituted orsubstituted as described above. Examples of urea include, withoutlimitation, NHC(O)NHCH₃, NHC(O)NHCH₂CH₃, NHC(O)NHCH₂CH₂CH₃, andNHC(O)NHCH₂CH₂CH₂CH₃.

“Alkylaminocarbonyl” refers to

C(O)NH(alkyl) or

C(O)N(alkyl)(alkyl) where the alkyl groups are independently defined andindependently unsubstituted or substituted as described above. Examplesof alkylaminocarbonyl include, but are not limited to, CH₃NHCO,CH₃CH₂NHCO, CH₃CH₂CH₂NHCO, and CH₃CH(CH₃)NHCO.

It is to be noted that the term “a” or “an” refers to one or more. Assuch, the terms “a” (or “an”), “one or more,” and “at” least one areused interchangeably herein.

The words “comprise”, “comprises”, and “comprising” are to beinterpreted inclusively rather than exclusively. The words “consist”,“consisting”, and its variants, are to be interpreted exclusively,rather than inclusively.

As used herein, the term “about” means a variability of 10% from thereference given, unless otherwise specified.

The term “regulation” or variations thereof as used herein refers to theability of a compound of formulae (I-VI) to inhibit one or morecomponents of a biological pathway.

As used herein, “mitigate” refers to reduce in an objectively orsubjectively measurable way by the administration of an effective amountof a compound of formulae (I-VI). In the context of pain, for example,mitigate could mean a measurable change in some biological or chemicalmarker, measurement of a change in degree of binding affinity, etc.consistent with a reduction in pain or could be that a patientexperiences a reduction in pain frequency, duration or intensity, or animproved quality of life apparently due to reduction in pain or ahealthcare provider observes that the patient experiences a reduction inpain frequency, duration or intensity, or an improved quality of lifeapparently due to reduction in pain. In the context of respiratoryconditions, and again for illustrative purposes only, mitigate couldmean a measurable change in some biological or chemical marker,measurement of a change in degree of binding affinity, etc. consistentwith a reduction in symptomology or lessoning of the condition or couldbe that a patient, again for example, experiences less frequent or lessintense cough, experiences less labored breathing, etc.

As used herein, the terms “subject” and “patient” are usedinterchangeably and include a mammal, e.g., a human, mouse, rat, guineapig, dog, cat, horse, cow, pig, or non-human primate, such as a monkey,chimpanzee, baboon or gorilla.

As used herein, the terms “disease”, “disorder” and “condition” are usedinterchangeably, to indicate an abnormal state in a subject.

Unless defined otherwise in this specification, technical and scientificterms used herein have the same meaning as commonly understood by one ofordinary skill in the art and by reference to published texts, whichprovide one skilled in the art with a general guide to many of the termsused in the present application.

Pharmaceutical compositions described herein comprise a compound offormula (I) (which as used herein, includes compounds of formulae(II-VI) optionally with other pharmaceutically inert or inactiveingredients. In one embodiment, the pharmaceutically inert or inactiveingredient is one or more pharmaceutically acceptable carrier orexcipient. Also contemplated is combining a compound of formulae (I-VI)with one or more therapeutic agents, i.e., active ingredients, asdescribed below. In a further embodiment, a compound of formulae (I-VI)is combined with one or more inert/inactive ingredients and one or moretherapeutic agents.

The pharmaceutical compositions of the invention comprise an amount of acompound of formulae (I-VI) that is effective for regulating P2X₃ orP2X_(2/3), such as in the treatment of pain and/or respiratorydysfunctions in a subject. Specifically, the dosage of the compounds offormulae (I-VI) to achieve a therapeutic effect will depend on factorssuch as the formulation, pharmacological potency of the drug, age,weight and sex of the patient, condition being treated, severity of thepatient's symptoms, specific compounds of formulae (I-VI), route ofdelivery, and response pattern of the patient. It is also contemplatedthat the treatment and dosage of the compounds of formulae (I-VI) may beadministered in unit dosage form and that one skilled in the art wouldadjust the unit dosage form accordingly to reflect the relative level ofactivity. The decision as to the particular dosage to be employed (andthe number of times to be administered per day) is within the discretionof the ordinarily-skilled physician, and may be varied by titration ofthe dosage to the particular circumstances to produce the therapeuticeffect. Further, one of skill in the art would be able to calculate anychanges in effective amounts of any one of the compounds of thecompositions due to changes in the composition components or dilutions.In one embodiment, the compositions may be diluted 2-fold. In anotherembodiment, the compositions may be diluted 4-fold. In a furtherembodiment, the compositions may be diluted 8-fold.

For treating of pain, the details of dosage are described as follows.

In one embodiment, the therapeutically effective amount is about 0.0001%to about 25% w/v (i.e., weight of drug per mL of formulation). Inanother embodiment, the therapeutically effective amount is less thanabout 20% w/v, about 15% w/v, about 10% w/v, about 5% w/v, or about 1%w/v. In another embodiment, the therapeutically effective amount isabout 0.0001% to about 10% w/v. In a further embodiment, thetherapeutically effective amount is about 0.005 to about 5% w/v. Instill a further embodiment, the therapeutically effective amount isabout 0.01 to about 5% w/v. In still a further embodiment, thetherapeutically effective amount is about 0.01% w/v, about 0.05% w/v,about 0.1% w/v, about 0.2% w/v, about 0.3% w/v, about 0.4% w/v, about0.5% w/v, about 0.6% w/v, about 0.7% w/v, about 0.8% w/v, about 0.9%w/v, about 1% w/v, about 2% w/v, about 3% w/v, about 4% w/v, or about 5%w/v. In one embodiment, the therapeutically effective amount of thecompounds of formulae (I-VI) is about 0.2% w/v. In another embodiment,the therapeutically effective amount is about 0.5% w/v.

The therapeutically effect amount of the compounds of formulae (I-VI)may, therefore, be about 1 mg to about 1000 mg per dose based on a 70 kgmammalian, for example human, subject. In another embodiment, thetherapeutically effective amount is about 2 mg to about 250 mg per dose.In a further embodiment, the therapeutically effective amount is about 5mg to about 100 mg. In yet a further embodiment, the therapeuticallyeffective amount is about 25 mg to 50 mg, about 20 mg, about 15 mg,about 10 mg, about 5 mg, about 1 mg, about 0.1 mg, about 0.01 mg, about0.001 mg.

The therapeutically effective amounts may be provided on regularschedule, i.e., on a daily, weekly, monthly, or yearly basis or on anirregular schedule with varying administration days, weeks, months, etc.Alternatively, the therapeutically effective amount to be administeredmay vary. In one embodiment, the therapeutically effective amount forthe first dose is higher than the therapeutically effective amount forone or more of the subsequent doses. In another embodiment, thetherapeutically effective amount for the first dose is lower than thetherapeutically effective amount for one or more of the subsequentdoses. Equivalent dosages may be administered over various time periodsincluding, but not limited to, about every 2 hours, about every 6 hours,about every 8 hours, about every 12 hours, about every 24 hours, aboutevery 36 hours, about every 48 hours, about every 72 hours, about everyweek, about every 2 weeks, about every 3 weeks, about every month, aboutevery 2 months, about every 3 months and about every 6 months. Thenumber and frequency of dosages corresponding to a completed course oftherapy will be determined according to the judgment of a health-carepractitioner. The therapeutically effective amounts described hereinrefer to total amounts administered for a given time period; that is, ifmore than one compound of formulae (I-VI) is administered, thetherapeutically effective amounts correspond to the total amountadministered.

For treating respiratory dysfunctions, the details of dosage aredescribed as follows.

In one embodiment, the therapeutically effective amount is about 0.0001%to about 50% w/v (i.e., weight of drug per mL of formulation). Inanother embodiment, the therapeutically effective amount is about 0.5%to about 25% w/v. In a further embodiment, the therapeutically effectiveamount is about 1% to about 20% w/v. In still a father embodiment, thetherapeutically effective amount is about 5% to 10% w/v. In still afurther embodiment, the therapeutically effective amount is about 0.01%w/v, about 0.05% w/v, about 0.1% w/v, about 0.2% w/v, about 0.3% w/v,about 0.4% w/v, about 0.5% w/v, about 0.6% w/v, about 0.7% w/v, about0.8% w/v, about 0.9% w/v, about 1% w/v, about 2% w/v, about 3% w/v,about 4% w/v, or about 5% w/v.

The therapeutically effective amount of the compounds of formulae (I-VI)may, therefore, be about 0.001 mg to about 1,000 mg per dose based on a70 kg mammalian, for example human. In one embodiment, therapeuticallyeffective amount of the compounds of formulae (I-VI) is about 1 mg toabout 250 mg per dose. In another embodiment, therapeutically effectiveamount of the compounds of formulae (I-VI) is about 5 mg to about 100 mgper dose. In some embodiments, the compounds can be administered at adosage including, but not limited to, about 0.1 mg, 1 mg, about 5 mg,about 10 mg, about 15 mg, about 20 mg, about 25 mg, about 50 mg, about100 mg, about 200 mg, about 300 mg, about 400 mg, about 500 mg, about600 mg, about 700 mg, about 800 mg, about 900 mg, about 1,000 mg.

The therapeutically effective amounts may be provided on regularschedule, i.e., on a daily, weekly, monthly, or yearly basis or on anirregular schedule with varying administration days, weeks, months, etc.Alternatively, the therapeutically effective amount to be administeredmay vary. In one embodiment, the therapeutically effective amount forthe first dose is higher than the therapeutically effective amount forone or more of the subsequent doses. In another embodiment, thetherapeutically effective amount for the first dose is lower than thetherapeutically effective amount for one or more of the subsequentdoses. Equivalent dosages may be administered over various time periodsincluding, but not limited to, about every 2 hours, about every 6 hours,about every 8 hours, about every 12 hours, about every 24 hours, aboutevery 36 hours, about every 48 hours, about every 72 hours, about everyweek, about every 2 weeks, about every 3 weeks, about every month, aboutevery 2 months, about every 3 months and about every 6 months. Thenumber and frequency of dosages corresponding to a completed course oftherapy will be determined according to the judgment of a health-carepractitioner. The therapeutically effective amounts described hereinrefer to total amounts administered for a given time period; that is, ifmore than one compound of formulae (I-VI) is administered, thetherapeutically effective amounts correspond to the total amountadministered. The duration of treatment may last for days, weeks, monthsor years. In some embodiments, treatment lasts for two weeks. In someembodiments, treatment lasts one month. In some embodiments, treatmentcan proceed indefinitely.

The compounds of formulae (I-VI) may be administered by any route,taking into consideration the specific condition for which it has beenselected. The compounds of formulae (I-VI) may be delivered orally, byinjection, inhalation (including orally, intranasally andintratracheally), ocularly, transdermally (via simple passive diffusionformulations or via facilitated delivery using, for example,iontophoresis, microporation with microneedles, radio-frequency ablationor the like), intravascularly, cutaneously, subcutaneously,intramuscularly, sublingually, intracranially, epidurally, rectally,intravesically, and vaginally, among others.

For treating pain, the details of administration are described asfollows.

In one embodiment, the compounds of formulae (I-VI) may be administeredby injection, including microinjection, transdermally or topically. Inone embodiment, the amount of the compounds of formulae (I-VI) is about0.05% w/w to about 10% w/w of the preparation depending on the route ofadministration. In one embodiment, the compounds of formulae (I-VI) ispresent in a concentration of about 0.1% w/w to about 3% w/w. Thesecompositions may also contain stabilizing agents, antibacterial agents,buffers and may be manufactured in different dosage unit ampoules orbottles. When for ocular use, the amount of the compounds of formulae(I-VI) can be about 0.05% w/w to about 2.5% w/w. Compositions forinjection or infusion may be prepared as an aqueous suspension orsolution.

When used for dermal anesthesia, the amount of the compounds of formulae(I-VI) can be about 0.1% w/w to about 10% w/w. When used for non-ocular,topical (e.g., oral, nasal, rectal, urethral, vaginal) administrationthe amount of the compounds of formulae (I-VI) can be about 0.5% w/w toabout 5% w/w. When used as in an injection, the amount of the compoundsof formulae (I-VI) can be about 0.25% w/w to about 3% w/w forinjections. When used for infusions (e.g., for epidural, spinal orregional anesthesia), the amount of the compounds of formulae (I-VI) canbe about 0.1% w/w to about 3% w/w. In one embodiment, the compounds offormulae (I-VI) may be administered topically to the eye, e.g., assolutions, suspensions or ointments. Examples of ophthalmicallycompatible carriers which may be used include, without limitation, anaqueous solution, such as saline solution, oil solution or ointmentscontaining ophthalmically compatible preservatives, surfactants,buffers, and viscosity regulators. These compositions may also containstabilizing agents, antibacterial agents, and may be manufactured indifferent dosage units, suitable for ocular administration. Druginserts, either soluble or insoluble, may also be used.

In another embodiment, the compounds of formulae (I-VI) may beadministered by injection. Solutions for injection or infusion may beprepared as aqueous solutions. In one embodiment, the compounds offormulae (I-VI) is present in a concentration of about 0.1% w/w to about3% w/w. These solutions may also contain stabilizing agents,antibacterial agents, buffers and may be manufactured in differentdosage unit ampoules or bottles. In a further embodiment, the compoundsof formulae (I-VI) may be administered rectally. Dosage units for rectaladministration may be prepared in the form of ointments orsuppositories, which contain the compounds of formulae (I-VI) in amixture with a neutral fat base, or they may be prepared in the form ofgelatin-rectal capsules that contain the compounds of formulae (I-VI) ina mixture with, e.g., a vegetable oil or paraffin oil. Ointments,suppositories or creams containing at least one compound of formulae(I-VI) are useful for the treatment of hemorrhoids.

In still another embodiment, the compounds of formulae (I-VI) may beadministered transdermally. A variety of transdermal delivery systemsare known. For use in these systems, a compound of formulae (I-VI) maybe admixed with a variety of excipients which may include, e.g., pHadjusters, preservatives, and/or penetration enhancers in order to forma solution, ointment, cream, lotion, or gel. Such a composition may forma constituent of a transdermal delivery system (“patch” etc.).

A transdermal delivery system may be selected which permits or assists acompound of the invention in passing through the dermal layer and to thetargeted area, such as muscular tissues or a perineural space. Suchsystems may include formulation with skin penetration enhancers.Examples of skin penetration enhancers include physical enhancers(ultrasound, iontophoresis, electroporation, magnetophoresis,microneedle), vesicles, particulate systems (liposome, niosome,transfersome, microemulsion, solid lipid nanoparticle), and chemicalenhancers (sulfoxides, azones, glycols, alkanols, terpenes, etc.).Further examples of chemical enhancers include, e.g., propylene glycol,polyethylene glycol, isopropanol, ethanol, oleic acid,N-methylpyrrolidone, which increase the permeability of the skin to thecompounds, and permit the compounds to penetrate through the skin todeeper tissues. See, Sagie & Kohane, “Prolonged Sensory-Selective NerveBlockade”, PNAS, 2010(8): 3740-3745, 2010, which is herein incorporatedby reference, for additional examples of chemical enhancers.

As a further embodiment, the compounds of formulae (I-VI) may beinstilled via direct instillation into the bladder and/or urothelium. Inone example, a pharmaceutical composition containing a compound offormulae (I-VI) and one or more carriers or excipients is formulated forinstillation. For example, the compounds of formulae (I-VI) may beinstilled as a solution. In a further example, the compounds instilledmay be placed into said bladder or urothelium as an extended-releaseformulation. A variety of extended-release formulations may be utilizedfor this purpose and include, without limitation, solution, suspension,gel or other solid dosage form containing reservoirs, a drug coatedmaterial, a drug impregnated material, a liposomal-drug formulation,among others.

For treating respiratory dysfunction, in one embodiment, the compoundsof formulae (I-VI) may be administered by orally, injection,transdermally or topically as described above for treating pain.

In another embodiment, the compounds of formulae (I-VI) may beadministered by inhalation (including orally, intranasally andintratracheally). The route of inhalation is taught for example in U.S.Pat. Nos. 6,131,566; 8,198,354; 6,971,383; 8,075873 and 9,078,985. Threetypes of inhaler devices are known and commonly used to administer anddeliver drug therapies via inhalation. See U.S. Pat. No. 6,971,383. Themost common type used is pressurized metered dose inhaler (pMDI). Forthis route of administration, the compositions are formulated in asolution or suspension for use in a pressurized aerosol containertogether with a gaseous or liquefied propellant, e.g.,dichlorodifluoromethane, carbon dioxide, nitrogen, propane, and thelike. Inhalant drug aerosols can also be generated by the use ofnebulizers. Nebulizers deliver droplets in a size range that enables thedrug to reach the periphery of the lung through the air passage of apatient. A third type of inhaler is a dry powder inhaler (DPI).Typically the DPIs are configures to deliver a powdered drug or drugmixture which includes an excipient and/or other ingredients. In anotherembodiment, the compounds of formulae (I-VI) may be administered bynasal spray.

The pharmaceutical compositions containing a compound of formulae (I-VI)may be formulated neat or with one or more pharmaceutical carriersand/or excipients for administration. The amount of the pharmaceuticalcarrier(s) is determined by the solubility and chemical nature of thecompounds of formulae (I-VI), chosen route of administration andstandard pharmacological practice. The pharmaceutical carrier(s) may besolid or liquid and may incorporate both solid and liquidcarriers/matrices. A variety of suitable liquid carriers is known andmay be readily selected by one of skill in the art. Such carriers mayinclude, e.g., dimethylsulfoxide (DMSO), saline, buffered saline,cyclodextrin, hydroxypropylcyclodextrin (HPβCD), n-dodecyl-β-D-maltoside(DDM) and mixtures thereof. Similarly, a variety of solid (rigid orflexible) carriers and excipients are known to those of skill in theart. Such carriers may also be designed so as to undergo a statetransition when injected into the bladder (e.g., liquid to gel, liquidto solid, gel to solid); such materials are known to those skilled inthe art. Such carriers may also comprise a membrane, for examplecomprising a thermoelastic polymer, which defines a reservoir containinga solid or liquid composition. Such carriers may also comprise athermoelastic polymer matrix, in which a composition which contains acompound of formulae (I-VI) is embedded. The compounds of formulae(I-VI) can also be administered together with other-membrane stabilizers(local anesthetics), for example to form eutectic mixtures.

Although the compounds of formulae (I-VI) may be administered alone, itmay also be administered in the presence of one or more pharmaceuticalcarriers that are physiologically compatible. The carriers may be in dryor liquid form and must be pharmaceutically acceptable. Liquidpharmaceutical compositions may be sterile solutions or suspensions.When liquid carriers are utilized, they may be sterile liquids. Liquidcarriers may be utilized in preparing solutions, suspensions, emulsions,syrups and elixirs. In one embodiment, the compounds of formulae (I-VI)is dissolved a liquid carrier. In another embodiment, the compounds offormulae (I-VI) is suspended in a liquid carrier. One of skill in theart of formulations would be able to select a suitable liquid carrier,depending on the route of administration. The compounds of formulae(I-VI) may alternatively be formulated in a solid carrier. In oneembodiment, the composition may be compacted into a unit dose form,i.e., tablet or caplet. In another embodiment, the composition may beadded to unit dose form, i.e., a capsule. In a further embodiment, thecomposition may be formulated for administration as a powder. The solidcarrier may perform a variety of functions, i.e., may perform thefunctions of two or more of the excipients described below. For example,a solid carrier may also act as a flavoring agent, lubricant,solubilizer, suspending agent, filler, glidant, compression aid, binder,disintegrant, or encapsulating material. In one embodiment, a solidcarrier acts as a lubricant, solubilizer, suspending agent, binder,disintegrant, or encapsulating material. In another embodiment, thecarrier comprises a thermoelastic polymer defining a reservoircontaining at a minimum, at least one compound of formulae (I-VI) as asolid or liquid composition. In a further embodiment, such carrierscomprise a thermoelastic polymer matrix, in which a compositiondescribed herein is embedded.

The composition may also be sub-divided to contain appropriatequantities of the compounds of formulae (I-VI). For example, the unitdosage can be packaged compositions, e.g., packeted powders, vials,ampoules, prefilled syringes or sachets containing liquids.

In one embodiment, compositions described herein optionally contain oneor more carriers and one or more excipients, and one or more compoundsof formulae (I-VI). Examples of suitable excipients include withoutlimitation, surfactants, adjuvants, antioxidants, binders, buffers,coatings, coloring agents, compression aids, diluents, disintegrants,emulsifiers (e.g., polyoxyethylene fatty acid esters), emollients,encapsulating materials, fillers, flavoring agents, glidants,granulating agents, lubricants, metal chelators, osmo-regulators, pHadjustors (e.g., sodium hydroxide), preservatives, solubilizers,sorbents, stabilizing agents, sweeteners (such as saccharin),surfactants, suspending agents, syrups, thickening agents (e.g.,carboxypolymethylene or hydroxypropylmethylcellulose), penetrationenhancers (e.g., hydroxypolyethoxydodecane, DMSO, DMAC, DDM, etc.) orviscosity regulators (such as polymers to increase viscosity). See, forexample, the excipients described in the “Handbook of PharmaceuticalExcipients”, 5^(th) Edition, Eds.: Rowe, Sheskey, and Owen, APhAPublications (Washington, D.C.), Dec. 14, 2005, which is incorporatedherein by reference.

In one embodiment, the compositions may be utilized as inhalants. Forthis route of administration, compositions may be prepared as fluid unitdoses using a compound of formulae (I-VI) and a vehicle for delivery byan atomizing spray pump or by dry powder for insufflation.

In another embodiment, the compositions may be utilized as aerosols,i.e., oral or intranasal. For this route of administration, thecompositions are formulated for use in a pressurized aerosol containertogether with a gaseous or liquefied propellant, e.g.,dichlorodifluoromethane, carbon dioxide, nitrogen, propane, and thelike. Also provided is the delivery of a metered dose in one or moreactuations. In particular, the compositions containing a compound offormulae (I-VI) may be formulated for inhalation may also be formulatedin a pharmaceutically acceptable vehicle for the administration byinhalation with any of the well-known pharmaceutically acceptablemedically inert moiety such as carriers, including diluents, excipients,surfactants, and flavoring (see Remington's Pharmaceutical Sciences,18^(th) Ed., Gennaro, Mack Publishing Co., Easton, Pa. 1990 andRemington: The Science and Practice of Pharmacy, Lippincott, Williams &Wilkins, 1995).

In still another embodiment, the compounds of formulae (I-VI) can beadministered in an ingestible liquid, such as a syrup, elixir, solution,suspension, emulsion, micro-emulsion, nano-emulsion, colloid, liquidgel, or the like. In still another embodiment, the compounds of formulae(I-VI) can be administered in an oral film, lozenge, drop, or chewabledosage form which can include a pill, a gummy, a gum and the like. Theseroutes of administration may be particularly useful for treating theyoung, the elderly, anyone with swallowing issues, and animals. Thesetypes of dosage forms are also particularly useful in treating manyrespiratory conditions by use of the compounds of formulae (I-VI) alone,or with other agents which may be, for example, topically active.

In another embodiment, the compositions may be administered by amodified-release delivery device. “Modified-release” as used hereinrefers to delivery of a compound of formulae (I-VI) which is controlled,for example over a period of at least about 8 hours (e.g., extendeddelivery) to at least about 12 hours (e.g., sustained delivery). Suchdevices may also permit immediate release (e.g., therapeutic levelsachieved in under about 1 hour, or in less than about 2 hours). Those ofskill in the art know suitable modified-release delivery devices. Foruse in such modified-release delivery devices, the compounds of formulae(I-VI) is formulated as described herein.

Suitable modified release delivery devices include drug-elutingimplants. Such implants can comprise a thermoelastic polymer matrix,such as a silicon or ethylene vinyl acetate matrix, wherein one or morecompounds of formulae (I-VI), optionally with one or more excipients, isembedded. See, e.g., U.S. Pat. No. 7,736,665 and US Patent PublicationNo. US-2011/0280922, the disclosures of which are herein incorporated byreference. Other drug-eluting implants can comprise an “osmotic pump” orother mechanism by which a solution comprising one or more compounds offormulae (I-VI) (optionally with one or more excipients) containedwithin the device is forced out, for example through the implant wallsor through one or more apertures, by osmotic pressure which buildswithin the device once it is implanted into a subject. See, e.g., U.S.Pat. Nos. 5,035,891 and 6,464,688, the disclosures of which are hereinincorporated by reference. Still other drug-eluting implants cancomprise a hydrogel such as a polymethacrylate-based polymer (e.g., U.S.Pat. Nos. 5,292,515 and 5,266,325, the disclosures of which are hereinincorporated by reference), or a thermoelastic polymer, such as apolyurethane (e.g., U.S. Pat. Nos. 7,858,110 and 7,842,303, thedisclosures of which are herein incorporated by reference), which definea reservoir containing a solid or liquid composition comprising one ormore compounds of formulae (I-VI) optionally with one or moreexcipients. Still other drug-eluting implants can comprise abio-degradable or bio-erodable polymer and at least one or morecompounds of formulae (I-VI), optionally with one or more excipients.See, e.g., U.S. Pat. Nos. 4,906,474 and 5,633,002, the disclosures ofwhich are herein incorporated by reference.

Modified release of the compounds of formulae (I-VI) may also beachieved by injecting a composition comprising one or more of thesecompounds into the bladder tissue (e.g., into the urothelium ormuscularis propria) with a device that can be employed via an endoscopeinserted into the bladder or percutaneously. For example, one or morecompounds of formulae (I-VI) can be injected into the bladder tissue viaa needle, or a needleless device as described in US Patent PublicationNo. US-2011/0046600, the disclosure of which is incorporated byreference. A suitable needleless injection device includes the JetTouch™platform (American Medical Systems; Minnetonka, Minn.). The injectedcompounds can form a depot, and in certain embodiments, the one or morecompounds of formulae (I-VI) can be encapsulated in a bio-degradable orbio-erodable polymer, for example as described in U.S. Pat. Nos.5,480,656 and 6,036,976, the disclosures of which are incorporated byreference.

Modified release of the compounds of formulae (I-VI) may also beachieved by instilling a composition comprising one or more compounds offormulae (I-VI) and a material which solidifies or gels, for exampleonce instilled into the bladder or upon contact with the bladderurothelium, to coat at least a portion of the bladder wall. The one ormore compounds of formulae (I-VI) can then elute from the solidified orgelled material. See, e.g., U.S. Pat. Nos. 6,894,071; 5,575,815 and6,039,967, the disclosures of which are incorporated by reference.

In still a further embodiment, the compositions may be administeredtransdermally, i.e., via the use of a drug-eluting patch. In oneembodiment, the patch is an “iontophoretic” transdermal patch in whichone or more medication(s) is delivered using a simple or moresophisticated, e.g., microprocessor-controlled, electrical currentusing, for example, an on-board battery. In still a further embodiment,the patch is a “microneedle” transdermal patch which containsmicroneedles coated with or containing (in dissolvable ornon-dissolvable form) a pharmaceutical composition of the invention.See, e.g., U.S. Pat. Nos. 7,798,987 and 7,537,795, the disclosures ofwhich are herein incorporated by reference. The microneedles canthemselves be dissolvable or non-dissolvable; see, for example, the“microneedle” technology described in Sullivan, “Dissolving PolymerMicroneedle Patches for Influenza Vaccination”, Nature Medicine,16:915-920 (Jul. 18, 2010 online publication) and Lee, “DissolvingMicroneedle Patch for Transdermal Delivery of Human Growth Hormone”,Small, 7(4):531-539 (Jan. 4, 2011 online publication), which are hereinincorporated by reference. Other suitable transdermal delivery systemsinclude the radio-frequency ablations systems described in Sintov,“Radiofrequency-Driven Skin Microchanneling as a New Way forElectrically Assisted Transdermal Delivery of Hydrophilic Drugs”,Controlled Release 89: 311-320 (2003), and U.S. Pat. No. 7,558,625, thedisclosures of which are herein incorporated by reference.

Further examples of transdermal patches useful for administration of thecompounds of formulae (I-VI) include those described in U.S. Pat. Nos.5,411,738 and 5,827,528 and Prausnitz and Langer, “Transdermal drugdelivery”, Nature Biotechnology, 26(11):1261-1268, November 2006, whichare herein incorporated by reference. In one embodiment, a patch isapplied via a suitable adhesive on the skin, where it remains in placefor at least one hour. In a further embodiment, the patch remains inplace for about 1 hour and is replaced weekly, for a total of about 2 orabout 3 hours wear time. In another embodiment, the patch remains inplace for about 2 hours. In a further embodiment, the patch remains inplace for about 3 hours. In still another embodiment, the patch remainsin place for about 4 hours. In yet another embodiment, the patch remainsin place for longer or shorter periods of time.

Also contemplated is the administration of the compounds of formulae(I-VI) in combination with other medication(s) or therapeutic agent(s).In one embodiment, the compounds of formulae (I-VI) are combined withother medications or therapeutic agents in a single composition. Inother embodiments, the compounds of formulae (I-VI) may be administeredin one or more separate formulations from other compounds of formulae(I-VI), or other medications or therapeutic agents as described below.For treating pain, these other medications for combination with thecompounds of formulae (I-VI) can include, but are not limited to, TRPV1and TRPA receptor activators and inhibitors, inhibitors of voltage-gatedion channels, non-steroidal anti-inflammatory drugs (NSAIDs), steroids,inhibitors of Spleen Tyrosine Kinase and the JAK-STAT pathway, cytokineinhibitors or modulators, opioids, tricyclic antidepressants, aminetransporter inhibitors, and anticonvulsants (such as gabapentinoids).For treating respiratory conditions, the same other medications ortherapeutic agents just described for treating pain, including, inparticular, the steroidal, non-sterioidal, and opioid based analgesicsand anti-inflammatory agents, may be used in combination with thecompounds of formulae (I-VI). Other medications or therapeutic agentsthat can be used in combination for respiratory conditions includeanticholinergic agents and beta-receptor agonists.

In one embodiment, the compounds of the invention may be utilized forregulating P2X₃ or P2X_(2/3) (such as treating pain) when combined witha TRPV1 receptor activator. The term “TRPV1 receptor activator” as usedherein refers to any agent or stimulus that activates TRPV1 receptors onnociceptors or puriceptors and allows for entry of at least oneinhibitor of voltage-gated ion (e.g., sodium or calcium) channels. Inone embodiment, the TRPV1 receptor activator includes, but is notlimited to, capsaicin, dihydrocapsaicin and nordihydrocapsaicin,lidocaine, articaine, procaine, tetracaine, mepivicaine, bupivicaine,eugenol, camphor, clotrimazole, arvanil (N-arachidonoylvanillamine),anandamide, 2-aminoethoxydiphenyl borate (2APB), AM404, resiniferatoxin,phorbol 12-phenylacetate 13-acetate 20-homovanillate (PPAHV), olvanil(NE 19550), OLDA (N-oleoyldopamine), N-arachidonyldop amine (NADA),6′-iodoresiniferatoxin (6′-IRTX), Cl 8 N-acylethanolamines, lipoxygenasederivatives (such as 12-hydroperoxyeicosatetraenoic acid), inhibitorcysteine knot (ICK) peptides (vanillotoxins), MSKl 95(N-[2-(3,4-dimethylbenzyl)-3-(pivaloyloxy)propyl]-2-[4-(2-aminoethoxy)-3-methoxyphenyl]acetamide),JYL79(N-[2-(3,4-dimethylbenzyl)-3-(pivaloyloxy)propyl]-N′-(4-hydroxy-3-methoxybenzyl)-thiourea),hydroxy-α-sanshool, 2-aminoethoxydiphenyl borate, 10-shogaol,oleylgingerol, oleylshogaol, SU200(N-(4-tert-butylbenzyl)-N′-(4-hydroxy-3-methoxybenzyl)thiourea)nonivamide, and fatty acyl amides of tetrahydroisoquinolines. In anotherembodiment, the TRPV1 receptor activator is lidocaine, aprindine,benzocaine, butacaine, cocaine, dibucaine, encainide, mexiletine,oxetacaine (oxethazaine), prilocaine, proparacaine, procainamide,n-acetylprocainamide, chloroprocaine (nes ac aine, nescaine), dyclonine,etidocaine, levobupivacaine, ropivacaine, cyclomethycaine, dimethocaine(larocaine), propoxycaine, trimecaine, and sympocaine. In a furtherembodiment, the TRPV1 receptor activator is lidocaine. In anotherembodiment, the TRPV1 activator may be a detergent or a surfactant,examples of which may be found in commonly-used hygiene products such assoaps and shampoos (e.g., sodium lauryl sulfate). See, Lilja,“Surfactant-Induced TRPV1 activity A Novel Mechanism for EyeIrritation?” Technological Sciences, 99(1):174-180, 2007, which isincorporated herein by reference. In another embodiment, the TRPV1receptor activator is heat or inflammation (which is known to activateTRPV1 receptors).

In one embodiment, the therapeutically effective amount of the TRPV1receptor activator is about 0.0001% to about 10% w/v. One of skill inthe art would readily understand that the recited therapeuticallyeffective amount is based on the free base of the TRPV1 receptoractivator. By using this information and skill in the art, one would beable to determine the amount of the corresponding TRPV1 receptoractivator salt for use in the compositions and methods described herein.In another embodiment, the therapeutically effective amount is less thanabout 10% w/v, about 9% w/v, about 8% w/v, about 7% w/v, about 6% w/v,about 5% w/v, about 4% w/v, about 3% w/v, about 2% w/v, or about 1% w/v.In another embodiment, the therapeutically effective amount is about0.1% to about 5% w/v. In a further embodiment, the therapeuticallyeffective amount is about 0.5 to about 3% w/v. In yet anotherembodiment, the therapeutically effective amount is about 0.5 to about2% w/v. In another embodiment, the therapeutically effective amount of aTRPV1 receptor activator is about 2% w/v. In another embodiment, thetherapeutically effective amount is about 1% w/v. In a furtherembodiment, the therapeutically effective amount is about 0.5% w/v.

The therapeutically effect amount of the TRPV1 receptor activator may,therefore, be about 0.001 mg to about 100 mg per dose based on a 70 kgmammalian subject. In another embodiment, the therapeutically effectiveamount is about 0.1 mg to about 25 mg per dose. In a further embodiment,the therapeutically effective amount is about 1 mg to about 5 mg. In yeta further embodiment, the therapeutically effective amount is about 0.1mg, about 0.5 mg, about 1 mg, about 2 mg, about 3 mg, about 4 mg, about5 mg, about 6 mg, about 7 mg, or about 8 mg.

Provided herein also is a composition containing a compound of formulae(I-VI) and lidocaine. In one embodiment, the composition contains about0.01% to about 1% w/v of a compound of formulae (I-VI) and about 0.1% toabout 5% w/v of lidocaine. In another embodiment, the compositioncontains about 0.1% to about 0.7% w/v of a compound of formulae (I-VI)and about 1% to about 3% w/v of lidocaine. In a further embodiment, thecomposition contains about 0.2% to about 0.5% w/v of a compound offormulae (I-VI) and about 1% to about 3% w/v of lidocaine. In yetanother embodiment, the composition contains about 0.2% to about 0.5%w/v of a compound of formulae (I-VI) and about 2% w/v of lidocaine. Instill another embodiment, the composition contains about 0.2% w/v of acompound of formulae (I-VI) and about 2% w/v of lidocaine. In anotherembodiment, the composition contains about 0.5% w/v of a compound offormulae (I-VI) and about 2% w/v of lidocaine. As discussed above, thesecompositions may be further diluted. In one embodiment, thesecompositions may be diluted 2-fold. In another embodiment, thesecompositions may be diluted 4-fold.

Also contemplated for use in the pharmaceutical combinations and methodsdescribed below are inhibitors of voltage-gated ion channels. In oneembodiment, the voltage-gated ion channels are sodium or calcium ionchannels. In a further embodiment, the voltage-gated sodium channelinhibitor includes, without limitation, QX-314, N-methyl-procaine(QX-222), N-octyl-guanidine, 9-aminoacridine, and pancuronium. Inanother embodiment, the inhibitor of voltage-gated calcium channelsincludes, but is not limited to, D-890 (quaternary methoxyverapamil) andCERM 1 1888 (quaternary bepridil). In a further embodiment,voltage-gated ion channel inhibitors such as riluzole, mexilitine,phenytoin, carbamazepine, procaine, tocainide, prilocaine,diisopyramide, bencyclane, quinidine, bretylium, lifarizine,lamotrigine, flunarizine, articaine, bupivicaine, mepivicaine,fluspirilene, orphenadrine, phenbenzamine, bepridil, pimozide,penfluridol, fluspirilene, propiverine, disopyramide, methadone,tolterodine, tridihexethyl salts, tripelennamine, mepyramine,brompheniramine, chlorpheniramine, dexchlorpheniramine, carbinoxamine,levomethadyl acetate, gallopamil, verapamil, devapamil, tiapamil,emopamil, dyclonine, pramoxine, lamotrigine, mibefradil, gabapentin,amiloride, diltiazem, nifedipine, nimodipine, nitrendipine, cocaine,mexiletine, propafenone, quinidine, oxethazaine, articaine, riluzole,bencyclane, lifarizine, and strychnine may be combined with thecompounds of formulae (I-VI).

Membrane permeable inhibitors of voltage-gated ion channels may also beutilized in combination with the compounds of formulae (I-VI) in thecompositions, combinations, or methods described herein. In oneembodiment, the membrane permeable inhibitor of voltage-gated ionchannels includes, but is not limited to, cocaine, carbamazepine,disopyramide, lamotrigine, procainamide, phenytoin, oxcarbazepine,topiramate, zonisamide, tetracaine, ethyl aminobenzoate, prilocaine,disopyramide phosphate, flecainide acetate, mexiletine, propafenone,quinidine gluconate, quinidine polygalacturonate, chloroprocaine,dibucaine, dyclonine, mepivacaine, pramoxine, procaine, tetracaine,oxethazaine, propitocaine, levobupivacaine, bupivacaine, lidocaine,moricizine, tocainide, proparacaine, ropivacaine, quinidine sulfate,encainide, ropivacaine, etidocaine, moricizine, quinidine, encainide,flecainide, tocainide, fosphenytoin, chloroprocaine, dyclonine,L-(−)-1-butyl-2′,6′-pipecoloxylidide, and pramoxine.

As noted above, additionally, one or more agents may be used to treatpain in addition to and in conjunction with the compounds of formulae(I-VI) and these include, i.e., analgesics, may be used in conjunctionwith a combination of the invention in the methods, compositions, andkits described herein. Such agents include, but are not limited to,non-steroidal anti-inflammatory drugs (NSAIDs), opioids, tricyclicantidepressants, amine transporter inhibitors, and anticonvulsants (suchas gabapentinoids).

The compounds of formulae (I-VI) may be administered together with avasoconstrictor, e.g., epinephrine or vasopressin, when utilized ininjectable solutions.

The compounds of formulae (I-VI) may be combined with glucose ordextrose when utilized for infusion or as a regional analgesic oranti-pruritic.

Further, the compounds of formulae (I-VI) may be combined withthickening agents to form a jelly, or may also contain penetrationenhancers, for use in topical or dermal applications such as forurogenital topical procedures.

Sprays for topical anesthesia of the mouth and oropharynx may containthe compounds of formulae (I-VI), saccharin and/or alcohol.

The compounds of formulae (I-VI) may also be formulated as an ointmentfor administration to accessible mucous membranes. Also provided hereinare regimens, kits or packages of pharmaceutical formulations comprisingthe compounds of formulae (I-VI) or compositions described herein. Thekits may be organized to indicate a single formulation or combination offormulations to be taken at a designated time or times.

The kit may further comprise packaging or a container with the compoundsof formulae (I-VI) formulated for the delivery route. Suitably, the kitcontains instructions on dosing and an insert regarding the compounds offormulae (I-VI). Optionally, the kit may further contain instructionsfor monitoring local or circulating levels of product and materials forperforming such assays including, e.g., reagents, well plates,containers, markers or labels, and the like. Such kits are readilypackaged in a manner suitable for treatment of an indication. Forexample, the kit may also contain instructions for use of a patch, spraypump, nasal spray, inhaler (including aerosol, metered dose, and drypowder inhalers), nebulizer, or other delivery device. Other suitablecomponents to include in such kits will be readily apparent to one ofskill in the art, taking into consideration the indication and thedelivery route and may contain lubricants, antiseptic solutions andlocal anesthetic agents to facilitate the placement of the deliverydevice.

The compounds of formulae (I-VI) or compositions described herein can bea single dose or for continuous or periodic discontinuousadministration. For continuous administration, a package or kit caninclude the compounds of formulae (I-VI) in each dosage unit, e.g.,solution, lotion, tablet, pill, drug-eluting unit/patch or other unitdescribed above or utilized in drug delivery, and optionallyinstructions for administering the doses less-than-daily, daily, weekly,or monthly, for a predetermined length of time or as prescribed. Whenthe compounds of formulae (I-VI) is to be delivered periodically in adiscontinuous fashion, a package or kit can include placebos duringperiods when the compounds of formulae (I-VI) is not delivered. Whenvarying concentrations of a composition, of the components of thecomposition, or the relative ratios of the compounds of formulae (I-VI)or agents within a composition over time, a package or kit may contain asequence of dosage units which provide the variability.

A number of packages or kits are known in the art for dispensingpharmaceutical agents for periodic oral use. In one embodiment, thepackage has indicators for each period. In another embodiment, thepackage is a foil or blister package, labeled ampoule, vial or bottle.

The packaging means of a kit may itself be geared for administration,such as an inhaler, syringe, pipette, eye dropper, catheter, cytoscope,trocar, cannula, pressure ejection device, or other such apparatus, fromwhich the formulation may be applied to an affected area of the body,such as the lungs, injected into a subject, delivered to bladder tissueor even applied to and mixed with the other components of the kit.

One or more components of these kits also may be provided in dried orlyophilized forms. When reagents or components are provided as a driedform, reconstitution generally is by the addition of a suitable solvent.It is envisioned that the solvent also may be provided in anotherpackage.

The kits may include a means for containing the vials or other suitablepackaging means in close confinement for commercial sale such as, e.g.,injection or blow-molded plastic containers into which the vials areretained. Irrespective of the number or type of packages and asdiscussed above, the kits also may include, or be packaged with aseparate instrument for assisting with the injection/administration orplacement of the composition within the body of an animal. Such aninstrument may be an inhaler, syringe, pipette, forceps, measuringspoon, eye dropper, catheter, cytoscope, trocar, cannula,pressure-delivery device or any such medically approved delivery means.

In one embodiment, a kit is provided and comprises a compound offormulae (I-VI). The compounds of formulae (I-VI) may be in the presenceor absence of one or more of the carriers or excipients described above.The kit may optionally contain instructions for administering thecompounds of formulae (I-VI) to a subject having pain.

In a further embodiment, a kit is provided and comprises a compound offormulae (I-VI) in a second dosage unit, and one or more of the carriersor excipients described above in a third dosage unit. The kit mayoptionally contain instructions for administering the compounds offormulae (I-VI) to a subject having pain.

The compounds of formulae (I-VI) may also be administered prior to,concurrently with, or subsequent to administration of additionaltherapeutic agents or non-medication related therapies. In oneembodiment, the compounds of formulae (I-VI) may be administered inconjunction with nerve stimulation, e.g., transcutaneous electricalnerve stimulation (TENS) or sacral nerve stimulation.

The compounds described herein are useful in regulating or modulatingconditions which are associated with the P2X₃ and/or P2X_(2/3) pathway.The term “regulation,” “modulation” or variations thereof as used hereinare used interchangeably and refer to the ability of a compound offormulae (I-VI) to inhibit or reduce the activity of one or morecomponents of a biological pathway. In one embodiment, “regulation”refers to inhibition of P2X₃ activity. In another embodiment,“regulation” refers to inhibition of P2X_(2/3) activity. In a furtherembodiment, regulation refers to dual inhibition of P2X₃ and P2X_(2/3)activity.

Accordingly, in one aspect, the methods, compositions, and kits of theinvention can be used to treat pain resulting from a number ofconditions. The term “pain” as used herein includes all types of pain.In one embodiment, the pain may be acute or chronic. In anotherembodiment, the pain may be nociceptive, dysfunctional, idiopathic,neuropathic, somatic, central, visceral, inflammatory, and/orprocedural. For example, the pain may be from a migraine, back pain,neck pain, gynecological pain, pre-labor or labor pain, orthopedic pain,post-stroke pain, post-surgical or procedural pain, post herpeticneuralgia, sickle cell crises, interstitial cystitis, urological pain(such as urethritis), dental pain, headache, pain from a wound or from amedical procedure such as surgery (such as bunionectomy or hip, knee orother joint replacement), suturing, setting a fracture, biopsy, and thelike. Pain may also occur in patients with cancer, which may be due tomultiple causes, such as inflammation, nerve compression, and mechanicalforces resulting from tissue distension as a consequence of invasion bya tumor and tumor metastasis into bone or other tissues. In oneembodiment, the cancer is bone cancer.

In one embodiment, the pain is neuropathic pain, such as post-herpeticneuralgia. In another embodiment, the pain is inflammatory pain. In afurther embodiment, the pain is nociceptive pain. In still anotherembodiment, the pain is procedural pain. In yet a further embodiment,the pain is caused by esophageal cancer, colitis, cystitis, irritablebowel syndrome, colitis or idiopathic neuropathy. In still anotherembodiment, the pain is caused by airway, bladder or visceral organdysfunction.

“Somatic pain” includes pain from bone, joint, muscle, skin, orconnective tissue.

“Central pain” includes pain arising as a consequence of brain trauma,stroke, or spinal cord injury.

“Visceral pain” includes pain from visceral organs, such as therespiratory or gastrointestinal tract and pancreas, the urinary tractand reproductive organs. In one embodiment, visceral pain results fromtumor involvement of the organ capsule. In another embodiment, visceralpain results from obstruction of hollow viscus. In a further embodiment,visceral pain results from inflammation as in cystitis or refluxesophagitis.

“Idiopathic pain” refers to pain which has no underlying cause or refersto pain caused by condition which remains undiagnosed.

“Dysfunctional pain” refers to pain which occurs in the absence of anoxious stimulus, tissue damage or a lesion to the nervous system. Inone embodiment, dysfunctional pain results from rheumatologic conditionssuch as arthritis and fibromyalgia, tension type headache, irritablebowel disorders and erythermalgia.

“Nociceptive pain” includes pain caused by noxious stimuli that threatento or actually injure body tissues. In one embodiment, nociceptive painresults from a cut, bruise, bone fracture, crush injury, burn, trauma,surgery, labor, sprain, bump, injection, dental procedure, skin biopsy,or obstruction. In another embodiment, nociceptive pain is located inthe skin, musculoskeletal system, or internal organs.

“Neuropathic pain” is pain due to abnormal processing of sensory inputby the peripheral or central nervous system consequent on a lesion tothese systems. In one embodiment, neuropathic pain is chronic andnon-malignant. In one embodiment, neuropathic pain is due to trauma,surgery, herniation of an intervertebral disk, spinal cord injury,diabetes, infection with herpes zoster (shingles), HIV/AIDS, late-stagecancer, amputation (such as mastectomy), carpal tunnel syndrome, chronicalcohol use, exposure to radiation, and as an unintended side-effect ofneurotoxic treatment agents, such as certain anti-HIV andchemotherapeutic drugs. In another embodiment, neuropathic pain is maybe described as “burning,” “electric,” “tingling,” or “shooting”.

The phrase “inflammatory pain” includes pain resulting from inflammationcaused by any number of factors. In one embodiment, inflammatory painoccurs due to tissue damage or inflammation. In another embodiment,inflammatory pain is due to injury (including joints, muscle, andtendons injuries), surgical procedures, infection, and/or arthritis.

“Procedural pain” includes refers to pain arising from a medicalprocedure. The medical procedure may include any type of medical, dentalor surgical procedure. In one embodiment, the procedural pain ispostoperative. In another embodiment, the pain is associated with aninjection, draining an abscess, surgery, dermatological, dentalprocedure, ophthalmic procedure, arthroscopy and use of other medicalinstrumentation, and/or cosmetic surgery.

A “migraine” is a headache due to activation of sensory fibersinnervating the meninges of the brain.

The term “treat”, “treating”, or any variation thereof is meant toinclude therapy utilized to remedy a health problem or condition in apatient or subject. In one embodiment, the health problem or conditionmay be eliminated permanently or for a short period of time. In anotherembodiment, the severity of the health problem or condition, or of oneor more symptoms characteristic of the health problem or condition, maybe lessened permanently, or for a short period of time. Theeffectiveness of a treatment of pain can be determined using anystandard pain index, such as those described herein, or can bedetermined based on the patient's subjective pain. A patient isconsidered “treated” if there is a reported reduction in pain or areduced reaction to stimuli that should cause pain.

In order to measure the efficacy of any of the methods, compositions, orkits described herein, a measurement index may be used. Indices that areuseful for the measurement of pain associated with musculoskeletal,immunoinflammatory and neuropathic disorders include a visual analogscale (VAS), a Likert scale, categorical pain scales, descriptors, theLequesne index, the WOMAC index, and the AUSCAN index, each of which iswell known in the art. Such indices may be used to measure pain,function, stiffness, or other variables.

Indices that are useful of the measurement of pain associated withinterstitial cystitis include the interstitial cystitis symptom index(ICSI), the interstitial cystitis problem index (ICPI), thepain-urgency-frequency score (PUF), the Wisconsin Symptom Instrument(UWI) and a visual analog scale (VAS) such as the Likert scale and othercategorical pain scales.

A visual analog scale (VAS) provides a measure of a one-dimensionalquantity. A VAS generally utilizes a representation of distance, such asa picture of a line with hash marks drawn at regular distance intervals,e.g., ten 1-cm intervals. For example, a patient can be asked to rank asensation of pain by choosing the spot on the line that best correspondsto the sensation of pain, where one end of the line corresponds to “nopain” (score of 0 cm) and the other end of the line corresponds to“unbearable pain”. This procedure provides a simple and rapid approachto obtaining quantitative information about how the patient isexperiencing pain. VAS scales and their use are described, e.g., in U.S.Pat. Nos. 6,709,406 and 6,432,937, the relevant disclosures of which areherein incorporated by reference.

A Likert scale similarly provides a measure of a one-dimensionalquantity. Generally, a Likert scale has discrete integer values rangingfrom a low value, e.g., 0, meaning no pain, to a high value, e.g., 7,meaning extreme pain. A patient experiencing pain is asked to choose anumber between the low value and the high value to represent the degreeof pain experienced. Likert scales and their use are described, e.g., inU.S. Pat. Nos. 6,623,040 and 6,766,319, the relevant disclosures ofwhich are herein incorporated by reference.

The Lequesne index and the Western Ontario and McMaster Universities(WOMAC) osteoarthritis (OA) index assess pain, function, and stiffnessin the knee and hip of OA patients using self-administeredquestionnaires. Both knee and hip are encompassed by the WOMAC, whereasthere is one Lequesne questionnaire for the knee and a separate one forthe hip. These questionnaires are useful because they contain moreinformation content in comparison with VAS or Likert scale. Both theWOMAC index and the Lequesne index questionnaires have been extensivelyvalidated in OA, including in surgical settings, e.g., knee and hiparthroplasty. Their metric characteristics do not differ significantly.

The AUSCAN (Australian-Canadian hand arthritis) index employs a valid,reliable, and responsive patient self-reported questionnaire. In oneinstance, this questionnaire contains 15 questions within threedimensions (Pain, 5 questions; Stiffness, 1 question; and Physicalfunction, 9 questions). An AUSCAN index may utilize, e.g., a Likert or aVAS scale.

The O'Leary-Sant score and IC Problem Index are self-administeredindices for measuring lower urinary tract symptoms.

The Pain-Urgency-Frequency symptom scale is balanced assessment ofurinary dysfunction, pelvic pain and symptoms associated with sexualintercourse and frequently used in conjunction with intravesicalpotassium chloride administration.

The UWI utilizes seven IC-related questions about frequency, urgency,noctuira and pain.

Other suitable indices that are useful for the measurement of paininclude the Pain Descriptor Scale (PDS), the Verbal Descriptor Scales(VDS), the Numeric Pain Intensity Scale (NPIS), the Neuropathic PainScale (NPS), the Neuropathic Pain Symptom Inventory (NPSI), the PresentPain Inventory (PPI), the Geriatric Pain Measure (GPM), the McGill PainQuestionnaire (MPQ), mean pain intensity (Descriptor DifferentialScale), numeric pain scale (NPS) global evaluation score (GES) theShort-Form McGill Pain Questionnaire, the Minnesota MultiphasicPersonality Inventory, the Pain Profile and Multidimensional PainInventory, the Child Heath Questionnaire, and the Child AssessmentQuestionnaire.

In one embodiment, the treatment methods described herein includeadministering a compound of formulae (I-VI) to a patient. Additional,optional agents, such as those described above for use in thecombination, may be administered to the patient prior to, concurrentlywith, or subsequent to the compounds of formulae (I-VI).

A variety of in vivo assays and animal models are useful for assessingthe ability of compounds to inhibit pain via internal sodium channelinhibition. These models may or may not involve opening (activation) ofTRPV1 channels via inducing pain through physical, mechanical, orchemical, e.g., capsaicin, means. Examples of suitable models include,e.g., those described in Binshtok, Anesthesiology, July 2009,111(1):127-137; Reis, Anesthesiology, July 2009, 111(1):122-126; Gerner,Anesthesiology, November 2008, 109(5):872-878; and Binshtok, Nature,October 2007, 449:607-610, the use of isolated bladder detrusor musclepreparations (Witte, Naunyn-Schmeideberg's Arch. Pharmacol. 2011,384:555-563), measurement of voiding frequency and volume in freelymoving animals (Clouse, 2012, Urology 79:1410e1-1410e6), measurement ofbladder urodynamics using cystometry in anesthetized animals (Shimizu,2000, British Journal of Pharmacology 131:610-616), which areincorporated by reference herein. However, for a variety of reasonswhich will be readily apparent to those of ordinary skill in the art,one may provide in vitro assays which allow for the identification ofcompounds with the properties. Described herein are several such invitro assays.

In one embodiment, a modified FLIPR® (Fluorometric Imaging Plate Reader)based assay system was developed which is capable of discriminatingbetween non-specific versus hTRPV1-mediated entry of test compounds.Advantageously, the assay system utilizes heat activated opening ofhTRPV1 channels followed by an assessment of internal sodium channelblock. The assay allows a permanently charged compound to selectivelyenter through opened hTRPV1 channels and that compound's potency ininhibiting sodium channels from the cytoplasm side of the same cell canbe assessed and quantified.

The modified FLIPR® assay utilizes cells which functionally expresshTRPV1. As used herein, the term “functionally express” includes thosecells which express the human TRPV1 protein and which respond to stimuliwhich naturally open this channel, including, e.g., thermal (heat) orchemical (capsaicin, lidocaine, among others) means described herein.Suitable assays may include the calcium or membrane potential assaysdescribed herein, e.g., Example 49. However, other functional assays areknown in the art, e.g., voltage-clamp electrophysiology such as used byBinshtok, Nature 449(4) 607-610, 2007.

A suitable cell may be selected for expression of TRPV1 in cis or intrans and constructed using known techniques. In one embodiment, aneuroblastoma cell line such as N1E115 [CRL-2263] or ND7/23 [ECACCcatalog code: 92090903] is selected for expression of the hTRPV1.However, another neuroblastoma cell line may be selected, e.g., such asIMR-32 [CRL-127]; Neuro-2a [CRL-131]; NB41A3 [CRL-147]; B104-1-1[CRL-1887]; SK-N-AS [CRL-2137]; SK-N-F1 [CRL-2142]; SK-N-DZ [CRL-2149];SH-SY5Y [CRL-2266]; BE(2)-M17 [CRL-2267]; BE(2)-C [CRL-2268]; MC-IXC[CRL-2270]; SK-N-BE(2) (CRL-2271); CHP-212 (CRL-2273]; B35 [CRL-2754],which are available from the American Type Culture Collection, Manassas,Va. (US). Still other cell lines may be selected.

For a generation description of how the cells are produced, seegenerally, e.g., Sambrook, Molecular Cloning: A Laboratory Manual, ColdSpring Harbor Press, Cold Spring Harbor, N.Y. (US) 2001. In oneembodiment, a stable cell line may be prepared using the techniques inSambrook, using wild-type (wt) or recombinant hTRPV1 coding sequences.For example, preparation of one such cell line is described in detailherein (see Example 32). Preparation of another cell line is describedin International Patent Publication N. WO 2007/0066068; theLipofectamine® method may be employed for transfection of TRPV1 andhTRPV1 into Human Embryonic Kidney cells (HEK293) according to themanufacturers protocol (Gibco). To create a permanently expressing cellline, wt-TRPV1 transfected HEK cells can be subcloned in geneticin (0.6mg/mL) containing medium (DMEM containing 10% FCS, 100 U/mL penicillin,100 μg/mL streptomycin, and 250 ng/mL amphotericin B) and propagated fortwo weeks to allow selection. To obtain a TRPV1 permanently expressingsingle cell line, transfected cells can be plated in 96 well plates (1cell per well) and colonies grown from single cells were subsequentlytested for capsaicin responsiveness by measuring increases inintracellular calcium. The final clones selected, are taken throughthree further rounds of single cell cloning to ensure the cell lines arederived from a single cell. Variations on this methodology will bereadily apparent to one of skill in the art. In another embodiment,cells may be selected from a stable cell line to express the hTRPV1, intrans, e.g., from a viral vector or another suitable genetic element. Inone embodiment, a compound of formulae (I-VI) are used in an amountwhich is sufficient to mitigate a form of pain selected from the groupconsisting of migraine pain, neuropathic pain including post herpaticneuralgia, somatic pain, painful bladder syndrome including painassociated with interstitial cystitis, chronic low back pain, knee/jointpain associated with arthritis and inflammatory pain as measured by atechnique selected from the group consisting of a reduction of at leastone integer using the Likert Scale; a reduction of at least one unit(e.g., 1 cm on a scale of 10 cm) using the VAS Scale; or a reduction inthe WOMAC index for arthritis pain using the WOMAC questionnaire.

In other aspect, the methods, compositions, and kits of the inventioncan also be used to treat respiratory dysfunctions, signs or symptomsresulting from a number of respiratory diseases and disorders. The term“respiratory dysfunctions, signs or symptoms” as used herein includes,but not limited to, bronchial hyperactivity, bronchoconstriction,bronchospasm, hypersecretion, cough, cough hypersensitivity syndrome,wheezing, dyspnea, breathless, and chest tightness, due to a respiratorydisease or disorder. The term “respiratory disease or disorder” as usedherein includes, but not limited to, idiopathic pulmonary fibrosis(IPF), chronic obstructive pulmonary disease (COPD), asthma, upperrespiratory infection, interstitial lung disease (ILD), post-nasal drip,and bronchitis. The respiratory dysfunction may also be associated withgastroesophageal reflux disease (GERD), or be an iatrogenic cough,including cough associated with treatment with an ACE (AngiotensinConverting Enzyme) inhibitor, or be “smoker's cough”, that is, coughassociated with smoking.

The terms “cough” refers to cough including, but not limited to,sub-acute cough, chronic cough, treatment-resistant cough, idiopathicchronic cough, cough associated with upper respiratory infection,post-viral cough, iatrogenic cough (e.g., as induced by ACE-inhibitors),cough associated with smoking or a form of bronchitis, urge to coughassociated with any respiratory disease, cough-variant asthma,interstitial lung disease, and whooping cough.

The terms “acute cough” refers to a cough lasting up to two weeks induration. For instance, acute cough can be the result of an acutedisease, such as a cold or flu. An acute cough will disappear when theunderlying cause (e.g., cold or flu) is eliminated.

The terms “sub-acute cough” refers to a cough lasting between two andeight weeks. In some cases, a sub-acute cough follows a period in whicha subject is infected with a disease (e.g., cold or flu). A sub-acutecough is one that often remains after the underlying cause has beenremoved. For instance, a sub-acute cough is found post-infection (e.g.,post-viral infection).

The terms “chronic cough” refers to a persistent or refractory coughlasting longer than eight weeks that may not have an obvious underlyingcause and may not be associated with other respiratory diseases, such asasthma or COPD. Chromic cough is also characterized in that there are nohallmarks to define and diagnose it, in contrast to other respiratorydiseases (e.g., COPD). Another characteristic of chronic cough is that asubject suffering from chronic cough may be apparently normal in mostother aspects. Chronic cough is characterized by frequent coughing(e.g., at least 5-10 coughs per hour during daytime) and bothersomecoughing during sleep. Chronic cough can last for a period of years,including over a decade.

Various tools have been developed to assess cough in clinical practiceand in clinical studies. For example, the visual analog scale (VAS) asdescribed above for the assessment of pain, is also widely used for theassessment of cough severity. The Leicester cough questionnaire (LCQ)and the cough-specific quality of life questionnaire (CQLQ) are alsoused to assess the impact of chronic cough. Ambulatory devicesconsisting of a microphone and recording device, such as the Leicestercough monitor (LCM) and the VitaloJak, are effective tools to measurecough frequency, particularly in clinical studies. Use of these toolsprovides data in clinical practice and in clinical studies to measure areduction in cough frequency and/or severity for a patient, followingtreatment with a compound of formulae (I-VI).

In one embodiment, a compound of formulae (I-VI) are used in an amountwhich is sufficient to mitigate a respiratory condition selected fromthe group consisting of acute cough, chronic cough, and cough associatedwith idiopathic pulmonary fibrosis (IPF), as measured by one or moretechniques selected from the group consisting of the visual analog scale(VAS) for cough severity, the Leicester cough questionnaire (LCQ), thecough-specific quality of life questionnaire (CQLQ) and the Leicestercough monitor (LCM).

The following examples are illustrative only and are not intended tolimit the present invention. Compounds of formulas (I-VI) to be used forthe treatment of pain and compounds of formulas (I-VI) to be used forthe treatment of respiratory dysfunction, can be selected or prioritizedfor each indication on the basis of the in vitro potency for inhibitionof P2X₃ or P2X_(2/3), or for inhibition of both P2X₃ and P2X_(2/3), asmeasured using in vitro studies as described herein, and usinginformation from non-clinical in vivo pharmacokinetic studies and animalmodels for pain (as described herein) and animal models for respiratorydysfunction. Such models for respiratory dysfunction include, but arenot limited to, the guinea pig model of citric acid induced cough[Kamei, Takahashi, Yoshikawa, and Saitoh, Eur J Pharmacol 528, p 158-161(2005); Kamei and Takahashi, Eur J Pharmacol 547, p 160-164, (2006)],and other models as reviewed by Lewis et al., in Pulm Pharmacol Ther.20, p 315-333 (2007) and by Bolser, in Pulm Pharmacol Ther. 17, p383-388 (2004).

EXAMPLES

Unless otherwise stated, all the raw materials are purchased fromcommercially available common suppliers. ¹H-NMR spectra were recordedusing trimethylsilane (TMS) as the internal reference for CDCl₃dissolved compounds. For DMSO-d₆ and CD₃OD dissolved compounds theinstrument was calibrated at δ 2.5 and 3.3 ppm respectively. Thechemical shift values are quoted in δ (parts per million).

For LCMS analysis LCMS/MS API 2000 (Applied Biosystem) instrument wasused. The columns included:

-   -   Column U: YMC, 4.6×50 mm, 5μ    -   Column V: Zorbax® C18 column, 4.6×50 mm, 5μ    -   Column W: Zorbax® Extend C18 column, 4.6×50 mm, 5μ    -   Column X: Gemini® NX C18 column, 4.6×50 mm, 5μ    -   Column Y: Xbridge® C18 column, 4.6×50 mm, 5μ    -   Column Z: Reprosil® column, 4.6×50 mm, 5μ    -   The eluent (solvent) typically included (acidic or basic buffer        as aqueous phase):    -   A channel: (i) 0.05% formic acid in water;    -   (ii) 10 mM ammonium acetate in water; or    -   (iii) 0.05% TFA in water.    -   B channel; acetonitrile (organic phase).    -   The detector was UV measured at dual wavelengths: 220 and 260        nm.

The LCMS gradients were one of the following:

1. LCMS Reaction Monitoring and Final Compound Analysis Method (forGeneral Polarity Compounds)

-   -   Gradient condition: 5 mM run time    -   Time Programs: P1:10 mM ammonium acetate in water/acetonitrile        -   Q1: 0.05% TFA in water/acetonitrile,    -   R1: 0.05% formic acid in water/acetonitrile.    -   The gradient varied acetonitrile from 10% to 90% to 10%.

Flow rate: 1.2 mL/min.

2. LCMS Reaction Monitoring and Final Compound Analysis Method in 12 mMRun (for Close Eluting Compounds):

-   -   Gradient condition: 12 mM run time    -   Time Programs: P2: 10 mM ammonium acetate in water/acetonitrile    -   Q2: 0.05% TFA in water/acetonitrile    -   R2: 0.05% formic acid in water/acetonitrile    -   The gradient varied acetonitrile from 5% to 90% to 5%    -   Flow rate: 1.0 mL/min

3. LCMS after Method Development in HPLC—Gradient Conditions are as PerHPLC.

-   -   Mass spectral data was obtained using the following:    -   Ionization technique: ESI (Electron Spray Ionization) using API        (Atmospheric pressure Ionization) source    -   Declustering Potential: 10-70 V depending on the ionization of        compound    -   Mass range: 100-800 amu    -   Scan type: Q1    -   Polarity: +/−ve    -   Ion Source: Turbo spray    -   Ion spray voltage: +5500 for +ve mode and −4500 for −ve mode    -   Mass Source temperature: 200° C.

PREPARATION OF INTERMEDIATES

Few of the intermediates were used for the synthesis of the compoundswhich were synthesized by following sixteen (16) routes which are listedas examples below.

Preparation 1: 1-Pyrazin-2-yl-ethylamine

To a stirred solution of compound I (2 g; 16.4 mmol; 1 eq) in methanol(20 mL) were added ammonium acetate (12.6 g; 164 mmol; 10 eq) and sodiumcyanoborohydride (1 g; 16.4 mmol; 1 eq) and the resulting mixture wasstirred at 23° C. for 17 h. The mixture was quenched with water (50 mL)and the organic components were extracted with ethyl acetate (2×200 mL).The combined organic layers were washed with water and brine, dried overanhydrous sodium sulfate, filtered and the solvents were removed invacuo to afford crude compound, which was purified by silica gel(230-400 mesh) column chromatography, eluting with 10% MeOH/CH₂Cl₂, toafford the title compound (0.8 g, 40%). ¹H NMR (CDCl₃) δ 8.60 (s, 1H),8.49 (m, 1H), 8.43 (d, 1H, J=2 Hz), 4.20 (m, 1H), 1.45 (d, 3H, J=7 Hz).

Preparation 2: 4-Aminomethyl-1-methyl-1H-pyridin-2-one

Step 1: 4-Cyano-1-methyl-1H-pyridin-2-one

To a stirred solution of compound I (0.25 g; 2.08 mmol; 1 eq) in DMF (5mL) was added sodium hydride (0.12 g; 3.12 mmol; 1.5 eq) and theresulting mixture was stirred for 10 min at 0° C. To the mixture wasthen added methyl iodide (0.4 mL; 6.25 mmol; 3 eq) and the resultingmixture was stirred at 23° C. for 2 h. The mixture was diluted withwater (50 mL) and the organic components were extracted with ethylacetate (2×200 mL). The combined organic layers were washed with waterand brine, dried over anhydrous sodium sulfate, filtered and thesolvents were removed in vacuo to obtain the title compound (0.18 g,67%). ¹H NMR (DMSO-d₆) δ 7.93 (d, 1H, J=7 Hz), 7.00 (s, 1H), 6.52 (dd,1H, J=2, 7 Hz), 3.45 (s, 3H).

Step 2: 4-Aminomethyl-1-methyl-1H-pyridin-2-one

To a stirred solution of compound II (1.67 g; 11.9 mmol; 1 eq) inmethanol (80 mL) was added concentrated HCl (1 mL) followed by 10% Pd/C(1.6 g) and the resulting mixture was stirred under hydrogen atmosphereat a pressure of 50 psi for 4 h in a Parr autoclave. The mixture wasfiltered through a Celite® bed, washed with methanol and solvent of thefiltrate was removed in vacuo to obtain the title compound (2 g, 92%).¹H NMR (DMSO-d₆) δ 8.55 (brs, 1H), 7.72 (d, 1H, J=7 Hz), 6.46 (s, 1H),6.31 (dd, 1H, J=2, 7 Hz), 3.86 (m, 2H), 3.40 (s, 3H).

Preparation 3: 6-Methyl-1-oxypyridin-3-yl)methylamine hydrochloride

Step 1: 6-Methyl-nicotinic acid methyl ester

To a stirred solution of compound I (40 g; 290 mmol; 1 eq) in methanol(0.75 L) was added sulfuric acid (40 mL) and the resulting mixture washeated at reflux for 17 h. The mixture was then evaporated to drynessand the pH was adjusted to 7 using saturated ice-cold aqueous NaHCO₃solution and solid NaHCO₃. The organic components were extracted fromthe aqueous layer with ethyl acetate (3×500 mL) and the combined organiclayers were washed with brine, dried over anhydrous sodium sulfate,filtered and the solvent was removed in vacuo to afford the titlecompound (33 g, 75%) as an off-white solid. ¹H NMR (CDCl₃) δ 9.06 (s,1H), 8.13 (dd, 1H, J=2, 8 Hz), 7.20 (d, 1H, J=8 Hz), 3.89 (s, 3H), 2.58(s, 3H). LCMS: m/z=152.4 [M+H]⁺, RT=2.36 minutes, (Program P1, ColumnW).

Step 2: (6-Methyl-pyridin-3-yl)methanol

To a stirred solution of compound II (21 g; 140 mmol; 1 eq) in dry THF(150 mL) was added 1M LiAlH₄ solution in THF (210 mL; 210 mmol; 1.5 eq)dropwise at −5° C. and after completion of the addition it was stirredat 23° C. for 2 h. The mixture was cooled to −10° C. and quenched withsodium sulfate decahydrate and ethyl acetate until effervescence ceased.The mixture was filtered through a Celite® pad and the filtrate wasevaporated to dryness to afford the title compound (17 g, 100%). ¹H NMR(DMSO-d₆) δ 8.37 (s, 1H), 7.59 (dd, 1H, J=2, 8 Hz), 7.19 (d, 1H, J=8Hz), 5.22 (t, 1H, J=6 Hz), 4.47 (d, 2H, J=6 Hz), 2.45 (s, 3H).

Step 3: Methanesulfonic acid (6-methyl-pyridin-3-yl)methyl ester

To a stirred solution of compound III (25 g; 200 mmol; 1 eq) in CH₂Cl₂(0.5 L) were added TEA (42.5 mL; 300 mmol; 1.5 eq) and methane sulfonylchloride (23.5 mL; 300 mmol; 1.5 eq) dropwise and the resulting mixturewas stirred at 23° C. for 1 h. The mixture was diluted with water (100mL) and the organic components were extracted with CH₂Cl₂ (2×200 mL).The combined organic layers were washed with water and brine, dried overanhydrous sodium sulfate, filtered, and the solvents were removed invacuo to afford the title compound (41 g, 100%).

Step 4: 3-Azidomethyl-6-methylpyridine

To a stirred solution of compound IV (43 g; 0.21 mol; 1 eq) in dry DMF(150 mL) was added sodium azide (139 g; 2.13 mol; 10 eq) and theresulting mixture was stirred at 23° C. for 17 h. The mixture wasquenched with water (500 mL) and the organic components were extractedwith ethyl acetate (2×200 mL). The combined organic layers were washedwith water and brine, dried over anhydrous sodium sulfate, filtered, andthen concentrated in vacuo to obtain compound (31.6 g, 100%) as crudematerial.

Step 5: (6-Methyl-pyridin-3-yl)methylamine

To a stirred solution of compound V (8 g; 50 mmol; 1 eq) in THF (250 mL)and water (5.7 mL) was added triphenyl phosphine (28 g; 100 mmol; 2 eq),and the resulting mixture was heated at reflux for 4 h. The mixture wasevaporated to dryness to obtain a crude material. The crude product waspurified by column chromatography, eluting with 10% MeOH/CH₂Cl₂, toafford the title compound (3 g, 46%). ¹H NMR (DMSO-d₆) δ 8.36 (s, 1H),7.61 (dd, 1H, J=2, 8 Hz), 7.16 (d, 1H, J=8 Hz), 3.67 (s, 2H), 2.49 (s,3H). LCMS: m/z=123.0 [M+H]⁺, RT=0.45 minutes, (Program R1, Column X).

Step 6: N-(6-Methyl-pyridin-3-yl)methyl)carbamic acid tert-butyl ester

To a stirred solution of compound VI (0.75 g; 6 mmol; 1 eq) in dryCH₂Cl₂ (10 mL) were added TEA (2.59 mL; 18 mmol; 3 eq), boc anhydride(1.55 mL; 6 mmol; 1.1 eq) and the resulting mixture was stirred at 23°C. for 17 h. The mixture was diluted with water (50 mL) and the organiccomponents were extracted with dichloromethane (2×100 mL). The combinedorganic layers were washed with water and brine, dried over anhydroussodium sulfate, filtered, and concentrated in vacuo to obtain the titlecompound (1.36 g, 100%). ¹H NMR (CDCl₃) δ 8.39 (s, 1H), 7.51 (d, J=8 Hz,1H), 7.10 (d, J=8 Hz, 1H), 4.84 (brs, 1H), 4.27 (d, J=4 Hz, 2H), 2.52(s, 3H), 1.44 (s, 9H); LCMS: m/z=222.8 [M+H]⁺, RT=2.69 minutes, (ProgramP1, Column W).

Step 7: N-(6-Methyl-1-oxy-pyridin-3-ylmethyl)carbamic acid tert-butylester

To a stirred solution of compound VII (1.36 g; 6 mmol; 1 eq) inchloroform (30 mL) were added mew chloroperbenzoic acid (1.32 g; 7 mmol;1.25 eq) and 2,6-ditertiary butyl-4-methyl phenol (6 mg; 0.3 mmol; 0.05eq) and the resulting mixture was heated at reflux for 2 days. Themixture was diluted with water (50 mL) and the organic components wereextracted with dichloromethane (2×100 mL). The combined organic layerswere washed with water and brine, dried over anhydrous sodium sulfate,filtered, and concentrated in vacuo to obtain the title compound (1.1 g,76%). ¹H NMR (CDCl₃) δ 8.21 (s, 1H), 7.19 (d, 1H, J=8 Hz), 7.11 (d, 1H,J=8 Hz), 5.00 (brs, 1H), 4.24 (d, 2H, J=5 Hz), 2.48 (s, 3H), 1.47 (s,9H). LCMS: m/z=239.0 [M+H]⁺, RT=2.06 minutes, (Program P1, Column W).

Step 8: (6-Methyl-1-oxy-pyridin-3-yl)methylamine hydrochloride

To a stirred solution of compound VIII (1.1 g; 4 mmol; 1 eq) in1,4-dioxane (5 mL) was added 4M HCl in 1,4-dioxane (20 mL) and theresulting mixture was stirred at 23° C. for 4 h. The solvents wereremoved in vacuo to afford the title compound (0.71 g, 89%). ¹H NMR(DMSO-d₆) δ 8.50 (m, 3H), 7.57 (d, 1H, J=8 Hz), 7.48 (d, 1H, J=8 Hz),4.02 (q, 2H, J=11 Hz), 2.38 (s, 3H). LCMS: m/z=139.0 [M+H]⁺, RT=0.45minutes, (Program P1, Column W).

The following amines were also prepared using the above mentionedprocedure:

Preparation 4: (2-Methoxypyrimidin-5-yl)methylamine hydrochloride

Step 1: 5-Cyano-2-methoxypyrimidine

To a stirred DMF (80 mL) solution of compound I (5 g; 26 mmol; 1 eq) ina reaction tube was added zinc cyanide (5 g; 53 mmol; 2 eq) and theresulting mixture was degassed with argon for 5 min. To the mixture wasthen added Pd(PPh₃)₄ (5 g; 5.20 mmol; 0.2 eq), and the resulting mixturewas degassed with argon for another 5 min. The reaction tube was sealedand heated at 115° C. for 3 h. The mixture was filtered through aCelite® pad and the filtrate was washed with saturated aqueous NaHCO₃solution, followed by brine. The organic layer was then dried overanhydrous Na₂SO₄ and evaporated to dryness to obtain a crude material.The crude product was purified by silica gel (100-200 mesh) columnchromatography, eluting with 50% EtOAc/hexanes to obtain the titlecompound (3.5 g, 100%). ¹H NMR (DMSO-d₆) δ 9.11 (s, 2H), 4.00 (s, 3H).LCMS: m/z=136.0 [M+H]⁺, RT=1.74 minutes, (Program P1, Column V).

Step 2: N-((2-Methoxy-pyrimidin-5-yl)methyl)carbamic acid tert-butylester

To a stirred solution of compound II (4.5 g; 33.3 mmol; 1 eq) inmethanol (230 mL) were added nickel chloride hexahydrate (3.15 g; 13.3mmol; 0.4 eq) and boc anhydride (14.4 g; 66.66 mmol; 2 eq) at 0° C. Tothe mixture was then added powdered NaBH₄ (8.7 g; 233 mmol; 7 eq) inportions and stirred at 23° C. for 17 h. The mixture was evaporated todryness, diluted with water and the organic components were extractedwith ethyl acetate (2×100 mL). The combined organic layers were washedwith brine, dried over anhydrous sodium sulfate, filtered, and thesolvents were removed in vacuo to obtain a dry residue which waspurified by silica gel (230-400 mesh) column chromatography using 2-5%methanol/dichloromethane as the eluent to afford the title compound (3.8g, 48%). ¹H NMR (DMSO-d₆) δ 8.46 (s, 2H), 4.06 (d, 2H, J=6 Hz), 3.88 (s,3H), 1.36 (s, 9H). LCMS: m/z=240.0 [M+H]⁺, RT=2.67 minutes, (Program P1,Column W).

Step 3: 2-Methoxypyrimidin-5-yl)methylamine hydrochloride

To a stirred solution of compound III (4 g; 28.98 mmol; 1 eq) in1,4-dioxane (20 mL) was added 4M HCl in 1,4-dioxane (30 mL) and themixture was stirred at 23° C. for 4 h. The solvent was removed in vacuoto afford the title compound (2.8 g, 95%). ¹H NMR (DMSO-d₆) δ 8.73 (s,2H), 4.03 (m, 2H), 3.89 (s, 3H). LCMS: m/z=140.0 [M+H]⁺, RT=0.59minutes, (Program P1, Column V).

Preparation 5: (2-Cyclopropylpyridin-5-yl)methylamine hydrochloride

Step 1: 2-Cyclopropyl-5-cyanopyridine

To a stirred solution of compound I (0.5 g; 3.62 mmol; 1 eq) in toluene(20 mL) and water (1 mL) in a reaction tube, was added cyclopropylboronic acid (0.46 g; 5.43 mmol; 1.5 eq) and the resulting mixture wasdegassed with argon for 5 min. To the mixture was then added K₃PO₄ (2.7g; 12.7 mmol; 3.5 eq), Pd(OAc)₂ (0.04 g; 0.18 mmol; 0.05 eq),tricyclohexyl phosphine (0.10 g; 0.36 mmol; 0.1 eq), and the resultingmixture was degassed with argon for another 5 min, then the reactiontube was sealed and heated at 110° C. for 3 h. The mixture was filteredthrough a Celite® pad and the filtrate was washed with saturated aqueousNaHCO₃ solution, followed by brine. The organic layer was then driedover anhydrous Na₂SO₄ and evaporated to dryness to obtain the crudematerial product. The crude material was purified by silica gel (100-200mesh) column chromatography, eluting with 5-30% EtOAc/hexanes to obtainthe title compound (0.28 g, 56%). ¹H NMR (CDCl₃) δ 8.67 (s, 1H), 7.75(dd, 1H, J=2, 8 Hz), 7.23 (m, 1H), 2.06 (m, 1H), 1.09 (m, 4H).

Step 2: (2-Cyclopropylpyridin-5-yl)methylamine hydrochloride

To a stirred solution of compound II (1.5 g; 11.11 mmol; 1 eq) inmethanol (80 mL) was added concentrated HCl (1 mL) followed by 10% Pd/C(1.6 g) and stirred under a hydrogen atmosphere at a pressure of 50 psifor 4 h in a Parr autoclave. The mixture was filtered through a Celite®pad, washed with methanol, and solvent from the filtrate was removed invacuo to afford the title compound (1.2 g, 78%). ¹H NMR (DMSO-d₆) δ 8.33(s, 1H), 7.64 (dd, 1H, J=2, 8 Hz), 7.27 (d, 1H, J=8 Hz), 1.89 (m, 1H),0.92 (m, 4H).

Preparation 6: 1-(2-Methyl-pyrimidin-5-yl)-ethylamine

Step 1: 3,3-Dimethoxy-2-methoxycarbonyl-1-propen-1-ol sodium salt

To a stirred solution of compound I (50 g; 337 mmol; 1 eq) in1,2-dimethoxy ethane (0.2 L) was added methyl formate (50 mL; 809 mmol;2.4 eq) and the mixture was cooled to −5° C. To the mixture was addedsodium hydride (60% in mineral oil, 17.5 g; 438 mmol; 1.3 eq) inportions and the resulting mixture was stirred at 50° C. untileffervescence had ceased. The mixture was then allowed to stir at 23° C.for 17 h. The mixture was filtered and the solid residue was collected,washed with ether and dried under reduced pressure to afford the titlecompound (63 g, 100%) as an off-white solid. ¹H NMR (CD₃OD) δ 8.88 (s,1H), 8.54 (s, 1H), 5.30 (s, 1H), 3.51 (s, 3H), 3.30 (s, 6H).

Step 2: 2-Methylpyrimidine-5-carboxylic acid methyl ester

To a stirred solution of compound II (60 g; 340 mmol; 1 eq) in dry DMF(1 L) was added acetamidine hydrochloride (38.6 g; 409 mmol; 1.2 eq) andthe resulting mixture was heated at 100° C. for 3 h. The mixture wasquenched with water (500 mL) and the organic components were extractedwith ethyl acetate (2×200 mL). The combined organic layers were washedwith water and brine, dried over anhydrous sodium sulfate, filtered andconcentrated in vacuo to obtain the title compound (27 g, 53%). ¹H NMR(CDCl₃) δ 9.13 (s, 2H), 3.93 (s, 3H), 2.77 (s, 3H).

The following amine was synthesized from compound III following theprocedure of preparation 3, steps 2-5.

Preparation 7: (S)-1-(4H-[1,2,4]-Triazol-3-yl)ethylamine hydrochloride

Step 1: (S)-(E)-Benzyl(1-(((dimethylamino)methylene)amino)-1-oxopropan-2-yl)carbamate

To (S)-benzyl (1-amino-1-oxopropan-2-yl)carbamate I (20 g, 90 mmol) wasadded DMF-DMA (100 mL) and the resulting mixture was heated at 40° C.for 40 min. The mixture was diluted with ethyl acetate and washed withwater and brine. The organic layer was dried over sodium sulphate,filtered and concentrated under reduced pressure to provide compound II(crude).

Step 2: [(S)-1-(4H[1,2,4]-Triazol-3-yl)ethyl]carbamic acid benzyl ester

To a stirred solution of compound II (crude) in dry DMF (109 mL) wasadded hydrazine (1M solution in THF) (135 mL, 135 mmol) and theresulting mixture was heated at 100° C. for 1.5 h. The mixture wasdiluted with ethyl acetate and washed with water and brine. The organiclayer was dried over anhydrous sodium sulfate, filtered and concentratedunder reduced pressure to obtain the crude product. The crude productwas purified by silica gel chromatography, eluting with 15-20%acetone/CH₂Cl₂, to obtain compound III as a white solid (5 g, 41%, 2steps). ¹H NMR (DMSO-d₆) δ 13.7 (s, 1H), 8.43 (s, 1H), 7.83 (s, 1H),7.35-7.30 (m, 5H), 5.01-4.98 (m, 2H), 4.80 (brs, 1H), 1.40 (s, 3H).LCMS: m/z=246.8 [M+H]⁺, RT=2.51 min (Program P1, Column V). Chiral SFC:99.07% (210 nm), RT 12.54 min (Mobile phase: A: ACN, B: MeOH)

Step 3: (S)-1-(4H-[1,2,4]-Triazol-3-yl)ethylamine hydrochloride

To a stirred solution of compound III (1 g; 4.06 mmol; 1 eq) in HCl (4Min 1,4-dioxane, 20 mL) was added 10% Pd/C (1 g) and the resultingmixture was stirred under a hydrogen atmosphere at a pressure of 60 psifor 16 h. The mixture was filtered through a Celite® pad and thefiltrate was evaporated to dryness to obtain compound IV (0.6 g, 100%).¹H NMR (DMSO-d₆) δ 8.71 (brs, 3H), 8.65 (s, 1H), 4.48 (m, 1H), 1.55 (d,3H, J=6 Hz). LCMS: m/z=113.2 [M+H]⁺, RT=0.47 minutes, (Program P1,Column W). Chiral SFC: 99.07% (210 nm), RT 12.54 min (Mobile phase: A:ACN, B: MeOH).

Preparation 8: (S)-2-Methyl-1-(4H-[1,2,4]triazol-3-yl)-propylamine

Step 1: ((S)-1-Carbamoyl-2-methyl-propyl)-carbamic acid benzyl ester

To a stirred solution of compound I (10 g, 39.84 mmol, 1 eq) in DMF (100mL) was added DIPEA (19.7 mL, 119.5 mmol, 3 eq) and HATU (18.17 g, 47.8mmol, 1.2 eq) at 0° C. and the resulting mixture was stirred for 15 min.To the mixture was added ammonium chloride (10.7 g, 199.2 mmol, 5 eq)and the resulting mixture was allowed to stir at 23° C. for another 16h. The mixture was poured into ice cold water (500 mL), the organiccomponents were extracted with EtOAc (3×500 mL) and the combined organiclayers were washed with aqueous ammonium chloride solution and brine.The organic layer was dried over anhydrous sodium sulfate, filtered andconcentrated to dryness. The crude product was recrystallized fromethanol to obtain the title compound (9.8 g, 98%) as an off-white solid.¹H NMR (400 MHz, DMSO-d₆) δ 7.35 (m, 6H), 7.12 (d, 1H, J=9 Hz), 7.01 (s,1H), 5.03 (s, 2H), 3.80 (t, 1H, J=8 Hz), 1.95 (m, 1H), 0.85 (m, 6H).LCMS: m/z=251.2 [M+H]⁺, RT=2.81 minutes, (Program P1, Column Y).

Step 2: ((S)-2-Methyl-1-thiocarbamoyl-propyl)-carbamic acid benzyl ester

To a stirred solution of compound II (5.5 g, 22 mmol, 1 eq) in dryCH₂Cl₂ (100 mL) at 23° C. was added Lawesson's reagent (5.5 g, 13.2mmol, 0.7 eq) and the mixture was heated at reflux for 2-3 h. Themixture was cooled to room temperature and concentrated in vacuo toobtain a crude material which was purified by gravity columnchromatography using silica gel (100-200 mesh), eluting with 1.5%MeOH/CH₂Cl₂ to obtain the title compound (1.8 g, 31%) as an off-whitesolid. ¹H NMR (400 MHz, DMSO-d₆) δ 9.63 (s, 1H), 9.21 (s, 1H), 7.32 (m,5H), 7.13 (d, 1H, J=9 Hz), 5.03 (s, 2H), 4.03 (m, 1H), 2.06 (m, 1H),0.95 (m, 6H). LCMS: m/z=267.2 [M+H]⁺, RT=3.10 minutes, (Program P1,Column Y).

Step 3: [(S)-2-Methyl-1-(4H-[1,2,4]triazol-3-yl)-propyl]-carbamic acidbenzyl ester

To a stirred solution of compound III (1.8 g; 6.7 mmol; 1 eq) in ethanol(80 mL) was added formic acid hydrazide (2 g; 33 mmol; 5 eq), mercury(II) chloride (2.38 g; 8.7 mmol; 1.3 eq) and the mixture was degassedwith argon for 15 min, then stirred at 23° C. for 17 h. The mixture wasthen filtered through the Celite® reagent and the filtrate wasevaporated to dryness. The residue was diluted with EtOAc (200 mL) andwashed with 20% aq. sodium carbonate solution. The organic layer wasthen dried over anhydrous sodium sulfate, filtered and concentratedunder reduced pressure to provide a crude compound. The crude materialwas dissolved in ethanol (100 mL) and heated at reflux for 17 h. Themixture was concentrated in vacuo to provide a crude compound which waspurified by silica gel (100-200 mesh) gravity column chromatographyeluting with 3% MeOH/CH₂Cl₂ to obtain the title compound (1.4 g, 74%) asa white solid. ¹H NMR (400 MHz, DMSO-d₆) δ 13.76 (brs, 1H), 8.44 (s,1H), 7.51 (m, 1H), 7.34 (m, 5H), 5.03 (m, 2H), 4.51 (m, 1H), 2.12 (m,1H), 0.90 (m, 3H), 0.79 (m, 3H).

Step 4: (S)-2-Methyl-1-(4H-[1,2,4]triazol-3-yl)-propylamine

To a stirred solution of compound IV (0.5 g; 1.84 mmol; 1 eq) in EtOH,degassed with argon, was added 10% Pd/C (1.5 g) and HCl in dioxane (4.0M solution, 10 mL) and the resulting mixture was stirred at 23° C. undera hydrogen atmosphere of 50 psi pressure in a Parr shaker for 10 h. Themixture was filtered through the Celite® reagent and the filtrate wasevaporated to dryness to afford the title compound (0.23 g, 90%) as anoff white solid. ¹H NMR (400 MHz, DMSO-d₆) δ 8.10 (brs, 3H), 7.86 (s,1H), 7.56 (s, 1H), 3.52 (m, 1H), 2.10 (m, 1H), 0.94 (m, 6H).

Preparation 9: (R)-1-(3-Methyl-[1,2,4]oxadiazol-5-yl)-ethylaminehydrochloride salt

Step 1: [(R)-1-(3-Methyl-[1,2,4]oxadiazol-5-yl)-ethyl]-carbamic acidtert-butyl ester

To a stirred solution of compound I (3 g, 15.9 mmol, 1 eq) in DMF (15mL) were added TEA (6.7 mL, 47.6 mmol, 3 eq), N-hydroxy acetamidinehydrochloride (1.5 g, 20.6 mmol, 1.3 eq) and T3P (50% in ethyl acetate,7 mL, 23.8 mmol, 1.5 eq) at 23° C. and the resulting mixture was heatedat 110° C. for 3 h. The mixture was cooled to room temperature andquenched with water. The organic components were extracted with ethylacetate (2×200 mL) and the combined extracts were washed with brine. Theorganic layer was dried over anhydrous sodium sulfate, filtered andconcentrated in vacuo to dryness. The crude product was purified bysilica gel (100-200 mesh) gravity column chromatography eluting with10-50% EtOAc/hexane to obtain the title compound (3 g, 83%) as stickyliquid. ¹H NMR (400 MHz, CDCl₃) δ 5.06 (m, 1H), 2.38 (s, 3H), 1.43 (s,9H).

Step 2: (R)-1-(3-Methyl-[1,2,4]oxadiazol-5-yl)-ethylamine hydrochloridesalt

To a stirred solution of compound II (3 g; 13.2 mmol; 1 eq) in1,4-dioxane (15 mL) at 0° C. was added 4 M HCl in 1,4-dioxane (53 mL)dropwise over a period of 30 min and the resulting mixture was stirredat 23° C. for 24 h. The mixture was concentrated in vacuo to obtain thetitle compound (2.1 g, 100%) as an off white solid. ¹H NMR (400 MHz,DMSO-d₆) δ 9.02 (brs, 3H), 4.86 (q, 1H, J=7 Hz), 2.39 (s, 3H), 1.60 (d,3H, J=7 Hz). The analytical chiral HPLC chromatogram showed that thecompound was not chirally pure.

Preparation 10: (R)-1-(5-Methyl-[1,3,4]oxadiazol-2-yl)-ethylaminetrifluoro acetic acid salt

Step 1: (R)-2-Amino-propionic acid methyl ester

To a stirred solution of compound I (10 g, 112.24 mmol, 1 eq) inmethanol (160 mL) was added thionyl chloride (16.3 mL, 224.5 mmol, 2 eq)at 0° C. and the resulting mixture was stirred at 23° C. for 10 h. Themixture was concentrated under reduced pressure and diluted with icecold sodium bicarbonate solution (300 mL). The organic components wereextracted with EtOAc (3×300 mL) and the combined extracts were washedwith brine. The organic phase was dried over anhydrous sodium sulfate,filtered and concentrated in vacuo to obtain the crude title compound(17.9 g, 15.6 g, 100%) as a semi solid material. ¹H NMR (400 MHz,DMSO-d₆) δ 8.56 (brs, 3H), 4.05 (m, 1H), 3.73 (s, 3H), 1.41 (d, 3H, J=7Hz).

Step 2: (R)-2-tert-Butoxycarbonylamino-propionic acid methyl ester

To a stirred solution of compound II (16.0 g, 114.7 mmol, 1 eq) inCH₂Cl₂ (60 mL) was added TEA (48.1 mL, 344.1 mmol, 3 eq) andBOC-anhydride (30 g 137.6 mmol, 1.2 eq) at 0° C. and the resultingmixture was stirred at 23° C. for 16 h. The mixture was poured into icecold water (500 mL), extracted with EtOAc (2×300 mL) and the combinedextracts were washed with brine. The organic layer was dried overanhydrous sodium sulfate, filtered and concentrated to dryness to obtaincrude title compound (20.0 g 72%) as an off white solid. ¹H NMR (400MHz, DMSO-d₆) δ 7.25 (d, 1H, J=7 Hz), 3.99 (m, 1H), 3.30 (s, 3H), 1.37(m, 9H), 1.22 (d, 3H, J=7 Hz).

Step 3: ((R)-1-Hydrazinocarbonyl-ethyl)-carbamic acid tert-butyl ester

To a stirred solution of compound III (10 g; 41.84 mmol; 1 eq) in THF(30 mL) in a reaction tube was added hydrazine hydrate (6.08 mL; 125.52mmol; 3 eq). The reaction tube was sealed and heated at 110° C. for 10h. The mixture was concentrated in vacuo to obtain crude title compound(11 g, 100%) as an off white solid. ¹H NMR (400 MHz, DMSO-d₆) δ 8.98(brs, 1H), 7.10 (brs, 1H), 6.82 (d, 1H, J=7 Hz), 6.48 (brs, 1H), 4.11(m, 1H), 1.30 (m, 9H), 1.10 (m, 3H).

Step 4: {(R)-1-[1-Ethoxy-eth-(E)-ylidene-hydrazinocarbonyl]-ethyl}-carbamic acid tert-butyl ester

A solution of compound IV (2.5 g; 9.16 mmol; 1 eq) in triethylorthoacetate (10.4 mL; 55 mmol; 6 eq) was heated at reflux for 2-3 h.The mixture was poured into ice cold water (100 mL) and the organiccomponents were extracted with EtOAc (2×100 mL) and the combinedextracts were washed with brine. The organic layer was dried overanhydrous sodium sulfate, filtered and concentrated in vacuo to obtainthe crude title compound (3.6 g, 100%) as a brown solid.

Step 5: [(R)-1-(5-Methyl-[1,3,4]oxadiazol-2-yl)-ethyl]-carbamic acidtert-butyl ester

A solution of compound V (3.5 g, 12.8 mmol, 1 eq) in acetic acid (7.3mL, 128 mmol, 10 eq) was heated at 60° C. under stirring for 5 h. Themixture was concentrated in vacuo to remove the acetic acid and theresidue was neutralized with ice cold sodium bicarbonate solution. Theorganic components were extracted with EtOAc (2×200 mL) and the combinedextracts were washed with brine. The organic layer was dried overanhydrous sodium sulfate, filtered and concentrated in vacuo, to obtainthe title compound (0.65 g, 23%) as a brown solid. ¹H NMR (400 MHz,DMSO-d₆) δ 7.56 (d, 1H, J=8 Hz), 4.82 (m, 1H), 2.46 (s, 3H), 4.40 (m,12H).

Step 6: (R)-1-(5-Methyl-[1,3,4]oxadiazol-2-yl)-ethylamine trifluoroacetic acid salt

To a solution of compound VI (0.5 g, 2.2 mmol, 1 eq) in CH₂Cl₂ (10 mL)was added trifluoroacetic acid (0.4 mL, 4.4 mmol, 2 eq) and theresulting mixture was stirred at 23° C. for 18 h. The mixture wasconcentrated under reduced pressure to remove the trifluoroacetic acidand the residue was washed with hexane to obtain the title compound(0.28 g, 100%) as a brown solid. ¹H NMR (400 MHz, DMSO-d₆) δ 8.72 (brs,3H), 4.18 (m, 1H), 2.54 (s, 3H), 1.56 (d, 3H, J=7 Hz).

Preparation 11:2-[4-(4,4,5,5-Tetramethyl-[1,3,2]dioxaborolan-2-yl)-pyrazol-1-yl]-acetamide

To a solution of compound I (5 g, 25.7 mmol; 1 eq) in acetonitrile in areaction tube (150 mL) was added bromo acetamide (5.68 g, 41.2 mmol; 1.6eq) and cesium carbonate (33.5 g, 102 mmol; 4 eq), and the reaction tubewas sealed and heated at 90° C. for 3 h. The mixture was cooled to roomtemperature and filtered through a Celite® pad and the filtrate wasconcentrated in vacuo to obtain the title compound (4.2 g, 65%), as acrude product which was directly used in next step without furtherpurification. ¹H NMR (400 MHz, DMSO-d₆) δ 7.67 (d, 1H, J=2 Hz), 7.57 (m,1H), 7.48 (brs, 1H), 7.42 (s, 1H), 4.76 (s, 2H), 0.89 (s, 12H)

Preparation 12: 5,5,5-Trifluoro-3-oxo-pentanoic acid methyl estersynthesis

To a stirred solution of Meldrum's acid (5 g, 34.7 mmol; 1 eq) in dryCH₂Cl₂ (5 mL) was added pyridine (3.07 mL; 38.2 mmol; 1.1 eq) at 0° C.followed by 3,3,3-trifluoropropionyl chloride I (5.5 g; 38.2 mmol; 1.1eq) and the resulting mixture was allowed to stir at 0° C. for 1 h. Thetemperature of the reaction was then increased to 23° C. and stirringwas continued for another 2 h. The mixture was concentrated underreduced pressure to remove volatiles and the resulting paste-likematerial was dissolved in methanol and heated at 80° C. for 5 h. Themixture was cooled to room temperature, concentrated under reducedpressure and diluted with aqueous ammonium chloride solution. Theorganic components were extracted with EtOAc, washed with 1N HClsolution, and brine. The organic layer was dried over anhydrous sodiumsulfate, filtered and concentrated to dryness to obtain the titlecompound (3.1 g, 50%), as a crude product which was directly used innext step without purification. ¹H NMR (DMSO-d₆) δ 3.87 (m, 2H), 3.70(s, 3H), 3.64 (s, 3H).

Preparation 13: 4,4-Difluoro-3-oxo-pentanoic acid methyl ester

To a stirred solution of diisopropyl amine in dry THF (150 mL) was addedn-butyllithium (2.3 M in hexane, 161 mL; 370.9 mmol; 2 eq) at −78° C.and the resulting mixture was allowed to stir at 0° C. for 40 min. Themixture was cooled to −78° C., ethyl acetate in dry THF was added dropwise and stirring was continued at −78° C. for 1 h. To the mixture,compound I (23 g; 185.4 mmol; 1 eq) in dry THF was added slowly and theresulting mixture was stirred for another 1 h at −78° C. The mixture wasallowed to stir at 23° C. for 16 h. The mixture was quenched withaqueous ammonium chloride solution (200 mL) and the organic componentswere extracted with EtOAc (2×700 mL). The combined organic layers werewashed with 1N HCl solution, brine and dried over anhydrous sodiumsulfate, then filtered. The filtrate was then concentrated under reducedpressure to obtain the title compound (23 g, 75%) as a crude materialwhich was directly used for the next step without any purification. ¹HNMR (DMSO-d₆) δ 4.21 (m, 4H), 3.93 (s, 4H), 2.17 (s, 2H), 1.77 (t, 3H),1.187 (m, 6H).

Preparation 14: Tributyl-(5-methyl-thiophen-2-yl)stannane

To a stirred solution of 2-bromo-5-methyl thiophene I (6 g, 33.9 mmol, 1eq) in dry THF (60 mL) cooled to −78° C., was added n-BuLi (14.7 mL, 2.3M in THF, 1 eq) and the resulting mixture was stirred for 45 min at −78°C. To the mixture was added tributyltin chloride (11 g, 33.9 mmol, 1 eq)and the resulting mixture was allowed to stir at −78° C. for another 1h. The mixture was then diluted with saturated aqueous ammonium chloridesolution, and the organic components were extracted with CH₂Cl₂ (2×50mL). The combined organic layers were washed with water and brine, driedover anhydrous sodium sulfate, filtered and concentrated to dryness toobtain crude tributyl-(5-methyl-thiophen-2-yl)stannane (13.1 g) whichwas directly used in subsequent reactions without any purification. ¹HNMR (CDCl₃) δ 6.95 (d, 1H, J=3 Hz), 6.87 (d, 1H, J=2 Hz), 2.53 (s, 3H),1.54 (m, 6H), 1.30 (m, 6H), 1.06 (m, 6H), 0.88 (m, 9H).

Following the same protocol, the below compounds were also prepared.

Preparation 15: Tributyl-(5-methyl-furan-2-yl)-stannane

To a stirred solution of 2-methylfuran I (3 g, 36.5 mmol, 1 eq) in dryTHF (20 mL) cooled to −78° C. was added n-butyllithium (15.9 mL, 2.3 Min THF, 1 eq) and the resulting mixture was stirred for 1 h at 0° C. Themixture was then cooled to −78° C. and tributyltin chloride was added(11.9 g, 36.5 mmol, 1 eq) and the resulting mixture was allowed to stirat 23° C. for 18 h. The mixture was then diluted with saturated aqueousammonium chloride solution, and the organic components were extractedwith ethyl acetate (2×50 mL). The combined organic layers were washedwith water, brine, dried over anhydrous sodium sulfate, filtered andconcentrated to dryness to obtain the title compound as a crude product(4.5 g) which was directly used for the next reaction without anypurification ¹H NMR (400 MHz, CDCl₃) δ 6.43 (d, 1H, J=3 Hz), 5.97 (d,1H, J=3 Hz), 2.32 (s, 3H), 1.70-1.40-1.28 (m, 6H), 1.32 (m, 12H), 0.91(m, 9H).

Preparation 16:8-(Cyclopropyl-propionyl-amino)-imidazo[1,2-a]pyridine-6-carboxylic acidethyl ester

Following the experimental procedure described for Example 8, compoundIV was prepared. Compound VIa was converted to Example 188 using thegeneral procedure described in Example 20.

Step 3a: 8-Cyclopropylamino-imidazo[1,2-a]pyridine-6-carboxylic acidethyl ester

To a stirred toluene solution of compound IV (1.5 g; 5.57 mmol; 1 eq) ina reaction tube was added cyclopropyl amine (0.47 g; 8.36 mmol; 1.5 eq)and the resulting mixture was degassed with argon for 5 min, followed byaddition of Cs₂CO₃ (2.72 g; 8.36 mmol; 1.5 eq), Pd₂(dba)₃ (0.25 g; 0.28mmol; 0.05 eq) and xantphos (0.32 g; 0.56 mmol; 0.1 eq). The mixture wasthen degassed again with argon for 5 min and then the reaction tube wassealed and heated to 110° C. for 2 h. The mixture was filtered through aCelite® pad and the filtrate was washed with saturated aqueous NaHCO₃solution, followed by brine. The organic layer was then dried overanhydrous Na₂SO₄, filtered and evaporated to dryness to obtain a crudematerial. The crude product was purified by silica gel (100-200 mesh)column chromatography, eluting with 20% EtOAc/hexanes to obtain thetitle compound (0.31 g, 23%) as a light brown solid. ¹H NMR (400 MHz,CDCl₃) δ 8.35 (s, 1H), 7.54 (s, 1H), 7.50 (s, 1H), 6.95 (s, 1H), 5.51(s, 1H), 4.39 (q, 2H, J=7 Hz), 2.59 (m, 1H), 1.40 (t, 3H, J=7 Hz), 0.83(m, 2H), 0.64 (m, 2H). LCMS: m/z=246.2 [M+], RT=3.13 minutes, (ProgramP1, Column V).

Step 4a:8-(Cyclopropyl-propionyl-amino)-imidazo[1,2-a]pyridine-6-carboxylic acidethyl ester

To a solution of compound Va (1 g, 4.08 mmol, 1 eq) in dry THF (50 mL)were added pyridine (0.67 mL, 8.16 mmol, 2 eq) and propionyl chloride(0.73 mL, 8.16 mmol, 2 eq) and the resulting mixture was heated atreflux with stirring under an argon atmosphere for 17 h. The mixture wascooled to room temperature and quenched with saturated aqueous sodiumbicarbonate solution (100 mL) and the organic components were extractedwith ethyl acetate (2×200 mL). The combined organic layers were washedwith brine (100 mL), dried over anhydrous sodium sulfate, filtered andthe filtrate was concentrated under reduced pressure to provide a crudecompound. The crude product was purified by Combiflash™ chromatographyeluting with 5% methanol/dichloromethane to obtain the title compound(0.83 g, 68%) as a grey solid. ¹H NMR (400 MHz, CDCl₃) δ 8.87 (s, 1H),7.69 (s, 2H), 7.47 (s, 1H), 4.40 (q, 2H, J=7 Hz), 3.35 (m, 1H), 2.47 (m,2H), 1.40 (t, 3H, J=7 Hz), 1.12 (t, 3H, J=7 Hz), 0.81 (m, 2H), 0.63 (m,2H). LCMS: m/z=302.2 [M+], RT=2.75 minutes, (Program P1, Column W).

Example 1(S)—N-(1-(4H-1,2,4-Triazol-3-yl)ethyl)-8-(S-ethyl-1,3,4-oxadiazol-2-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide

Step 1: 2-Aminonicotinic acid ethyl ester

To a stirred solution of compound I (10 g; 72 mmol; 1 eq) in ethanol(150 mL) was added thionyl chloride (15.7 mL; 217 mmol; 3 eq) dropwiseat 60° C. and the resulting mixture was heated at reflux for 17 h. Themixture was evaporated to dryness and pH was adjusted to 7 by addingice-cold saturated aqueous NaHCO₃ solution and solid NaHCO₃. The organiccomponents were extracted from the aqueous layer with ethyl acetate(3×500 mL), and the combined organic layers were washed with brinesolution, dried over anhydrous sodium sulfate, filtered and the solventwas removed in vacuo to afford the title compound (8 g, 66%) as anoff-white solid. ¹H NMR (DMSO-d₆) δ 8.20 (m, 1H), 8.05 (m, 1H), 7.13 (s,2H), 6.62 (m, 1H), 4.28 (q, 2H, J=7 Hz), 1.30 (t, 3H, J=7 Hz).

Step 2: 2-Amino-5-bromonicotinic acid ethyl ester

To a stirred solution of compound II (15 g; 90.36 mmol; 1 eq) in dry THF(150 mL) was added NBS (16 g; 90.36 mmol; 1 eq) in portions at 0° C. andthe resulting mixture was stirred at 23° C. for 18 h. The mixture waspoured into ice-cold saturated aqueous NaHCO₃ solution and the organiccomponents were extracted with ethyl acetate (3×200 mL). The combinedorganic layers were then washed with brine solution, dried overanhydrous sodium sulfate, filtered and evaporated to dryness to affordthe title compound (22 g, 100%) as an off white solid. ¹H NMR (DMSO-d₆)δ 8.29 (d, 1H, J=3 Hz), 8.12 (d, 1H, J=2 Hz), 7.31 (s, 2H), 4.29 (q, 2H,J=7 Hz), 1.30 (t, 3H, J=7 Hz). LCMS: m/z=245.0 [M+], 247.0 [M+2],RT=3.34 minutes, (Program P1, Column W).

Step 3: 6-Bromo-imidazo[1,2-a]pyridine-8-carboxylic acid ethyl ester

To a stirred solution of compound III (22 g; 90 mmol; 1 eq) in ethanol(500 mL) was added sodium bicarbonate (13 g; 179 mmol; 2 eq) andchloroacetaldehyde solution (˜50% aqueous solution, 60 mL; 449 mmol; 5eq) drop wise and the mixture was heated at reflux for 8 h. The mixturewas then evaporated to dryness and the pH was adjusted to 7 usingice-cold saturated aqueous NaHCO₃ solution and solid NaHCO₃. The organiccomponents were extracted from the aqueous layer with ethyl acetate(3×700 mL) and the combined organic layers were washed with brine, driedover anhydrous sodium sulfate, filtered and the solvents were removed invacuo to obtain a dry residue which was purified by silica gel (230-400mesh) column chromatography using 10-50% ethyl acetate/hexanes to affordthe title compound (14.5 g, 60%) as a brown solid. ¹H NMR (DMSO-d₆) δ9.16 (s, 1H), 8.02 (s, 1H), 7.84 (s, 1H), 7.70 (s, 1H), 4.38 (q, 2H, J=7Hz), 1.30 (t, 3H, J=7 Hz). LCMS: m/z=268.8 [M+], 270.8 [M+2], RT=2.77minutes, (Program P1, Column Y).

Step 4: 6-Bromo-imidazo[1,2-a]pyridine-8-carboxylic acid hydrazide

To a stirred solution of compound IV (5 g; 18.6 mmol; 1 eq) in ethanol(50 mL) was added hydrazine hydrate (9.3 g; 186 mmol; 10 eq) and theresulting mixture was heated at reflux for 5 h. The mixture was cooled,filtered and the solid residue was washed with hexane and dried underreduced pressure to obtain the title compound (4.5 g, 95%) as whitesolid. ¹H NMR (DMSO-d₆) δ 10.91 (s, 1H), 9.13 (d, 1H, J=2 Hz), 8.07 (s,1H), 7.96 (d, 1H, J=2 Hz), 7.74 (s, 1H) 4.86 (s, 2H).

Step 5: 6-Bromo-imidazo[1,2-a]pyridine-8-carboxylic acidN′-propionyl-hydrazide

To a stirred solution of compound V (4.5 g; 17.6 mmol; 1 eq) in dryCH₂Cl₂ (50 mL) at 0° C. were added TEA (7.6 mL; 52.9 mmol; 3 eq) andpropionyl chloride dropwise and the resulting mixture was allowed tostir at 23° C. for 2 h. The mixture was poured into saturated ice-coldaqueous NaHCO₃ solution and the organic components were extracted withethyl acetate (3×250 mL). The combined organic layers were washed withbrine, dried over anhydrous sodium sulfate, filtered and the solventswere removed in vacuo to obtain a dry residue which was purified bysilica gel (230-400 mesh) column chromatography using 0-5%methanol/dichloromethane as eluent to afford the title compound (1.2 g,23%) as an off white solid. ¹H NMR (DMSO-d₆) δ 11.97 (d, 1H, J=4 Hz),10.73 (d, 1H, J=4 Hz), 9.19 (d, 1H, J=2 Hz), 8.10 (s, 1H), 8.01 (d, 1H,J=2 Hz), 7.77 (s, 1H), 2.27 (q, 2H, J=8 Hz), 1.07 (t, 3H, J=8 Hz). LCMS:m/z=311.0 [M+], 313.0 [M+2], RT=2.29 minutes, (Program P1, Column W).

Step 6: 6-Bromo-8-(5-ethyl-[1,3,4]oxadiazol-2-yl)-imidazo[1,2-a]pyridine

A stirred solution of compound VI (1.2 g; 3.8 mmol; 1 eq) in dry POCl₃(20 mL) was heated at reflux for 2 h. The mixture was evaporated todryness and diluted with saturated aqueous NaHCO₃ solution. The organiccomponents were extracted with ethyl acetate (3×100 mL) and the combinedextracts were washed with brine, dried over anhydrous sodium sulfate,filtered and concentrated in vacuo to obtain a dry residue. The crudematerial was purified by silica gel (230-400 mesh) column chromatographyusing 0-5% methanol/dichloromethane as the eluent to obtain the titlecompound (0.6 g, 53%) as a light brown solid. ¹H NMR (DMSO-d₆) δ 9.18(s, 1H), 8.09 (s, 1H), 7.99 (s, 1H), 7.76 (s, 1H), 3.32 (s, 3H), 3.02(q, 2H), 1.36 (t, 3H). LCMS: m/z=293.0 [M+], 295.0 [M+2], RT=2.46minutes, (Program P1, Column W).

Step 7:8-(5-Ethyl-[1,3,4]oxadiazol-2-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester

To a solution of compound VII (0.6 g; 2.1 mmol; 1 eq) in methanol (20mL) was added diisopropylethyl amine (1.05 mL; 6.0 mmol; 3 eq), and theresulting solution was degassed with argon for 5 min, followed by anaddition of PdCl₂(dppf) (0.16 g; 0.21 mmol; 0.1 eq). The mixture wasthen degassed again with argon for 5 min, and heated to 90° C. for 16 hin an autoclave at a pressure of 50 psi under carbon monoxideatmosphere. The mixture was filtered through a Celite® pad and thefiltrate was washed with saturated aqueous NaHCO₃ solution, followed bybrine. The organic layer was dried over anhydrous Na₂SO₄ and finallyevaporated to dryness to obtain a crude material. The crude product waspurified by silica gel (100-200 mesh) column chromatography, elutingwith 0-10% methanol/dichloromethane as the eluent to obtain the titlecompound (0.3 g, 55%) as a light brown solid. LCMS: m/z=272.8 [M+H]⁺,RT=2.46 minutes, (Program P1, Column Y).

Step 8:3-Bromo-8-(5-ethyl-[1,3,4]oxadiazol-2-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester

To a stirred solution of compound VIII (0.32 g; 1.17 mmol; 1 eq) in dryTHF (15 mL) was added NBS (0.12 g; 0.71 mmol; 0.6 eq) in portions at 0°C. and the mixture was stirred for 30 min. The mixture was poured intoice-cold saturated aqueous NaHCO₃ solution and the organic componentswere extracted with ethyl acetate (3×50 mL). The organic layer was thenwashed with brine, dried over anhydrous sodium sulfate, filtered andevaporated to dryness to obtain a crude material. The crude product waspurified by silica gel (100-200 mesh) column chromatography, elutingwith 0-5% methanol/dichloromethane to obtain the title compound (0.21 g,51%) as a brown solid. ¹H NMR (DMSO-d₆) δ 8.94 (s, 1H), 8.36 (s, 1H),8.04 (s, 1H), 3.97 (s, 3H), 3.03 (q, 2H, J=8 Hz), 1.36 (t, 3H). LCMS:m/z=350.8 [M+], 352.8 [M+2], RT=2.70 minutes, (Program P1, Column Y).

Step 9:8-(5-Ethyl-[1,3,4]oxadiazol-2-yl)-3-(5-methyl-thiophen-2-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester

To a stirred solution of compound IX (0.21 g; 0.6 mmol; 1 eq) in drytoluene in a reaction tube was added compound VIa (0.27 g; 0.72 mmol;1.2 eq) and the resulting mixture was degassed with argon for 5 min. Tothe mixture was then added Pd(PPh₃)₄ (0.06 g; 0.06 mmol; 0.1 eq) and themixture was degassed further with argon for 5 min. The reaction tube wassealed and heated at 115° C. with stirring for 4 h. The mixture wasfiltered through a Celite® ad and the filtrate was washed with saturatedaqueous NaHCO₃ solution, followed by brine. The organic layer was driedover anhydrous Na₂SO₄ and the solvent was evaporated to dryness toobtain a crude material. The crude product was purified by silica gel(230-400 mesh) column chromatography eluting with 0-5%methanol/dichloromethane to obtain the title compound (0.22 g, 100%)which was used for the next step without further purification. LCMS:m/z=368.8 [M+H]⁺, RT=3.07 minutes, (Program P1, Column Y).

Step 10:8-(5-Ethyl-[1,3,4]oxadiazol-2-yl)-3-(5-methyl-thiophen-2-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid

To a solution of compound X (0.26 g, 0.7 mmol, 1 eq) in THF:methanol:H₂O(12 mL, 3:2:1) was added an aqueous solution (1 mL) of lithium hydroxidemonohydrate (0.09 g, 2.12 mmol, 3 eq) at 0° C. and the resulting mixturewas stirred at 23° C. for 3 h. The solvent of the mixture was removedunder reduced pressure, the residue was diluted with water, andacidified with 1N HCl to adjust the pH to 3. The precipitated solid wasfiltered and the residue was dried under vacuum to afford the titlecompound (0.12 g, 48%). ¹H NMR (DMSO-d₆) δ 9.08 (s, 1H), 8.37 (s, 1H),7.94 (s, 1H), 7.36 (d, 1H, J=4 Hz), 7.03 (m, 1H), 3.03 (q, 2H, J=8 Hz),2.56 (s, 3H), 1.36 (t, 3H, J=8 Hz). LCMS: m/z=355.0 [M+H]⁺, RT=2.06minutes, (Program P1, Column V).

Step 11:(S)—N-(1-(4H-1,2,4-Triazol-3-yl)ethyl)-8-(5-ethyl-1,3,4-oxadiazol-2-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide

To a stirred solution of compound XI (80 mg, 0.22 mmol, 1 eq) in DMF (5mL) was added DIPEA (0.12 mL, 0.7 mmol, 3 eq) and HATU (0.10 g, 0.3mmol, 1.2 eq) at 0° C. and the resulting mixture was allowed to stir for15 min. To the mixture was added(S)-1-(4H-[1,2,4]triazol-3-yl)-ethylamine hydrochloride (0.101 g, 0.7mmol, 3 eq) and the resulting mixture was stirred at 23° C. for another16 h. From the mixture, solvent was removed in vacuo and the residue wasdiluted with EtOAc and washed with saturated aqueous sodium bicarbonatesolution, aqueous ammonium chloride solution and brine. The organicphase was dried over anhydrous sodium sulfate, filtered and concentratedto dryness. The crude product was finally purified by silica gel(230-400 mesh) column chromatography eluting with 0-5% methanol/CH₂Cl₂to obtain the title compound (4 mg, 4%) as off white solid. ¹H NMR(DMSO-d₆) δ 13.86 (s, 1H), 9.39 (s, 1H), 9.19 (s, 1H), 8.53 (s, 1H),7.65 (s, 1H), 7.75 (m, 1H), 7.43 (d, 1H, J=4 Hz), 7.04 (d, 1H, J=3 Hz),5.36 (m, 1H), 3.05 (q, 2H, J=8 Hz), 2.55 (s, 3H), 1.56 (d, 3H, J=7 Hz),1.38 (t, 3H, J=8 Hz). LCMS: m/z=449.2 [M+H]⁺, RT=2.76 minutes, (ProgramP1, Column V).

Example 28-(2,5-Dimethyl-1H-imidazol-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide

Step 1: 6-Bromoimidazo-[1,2-a]pyridin-8-ylamine

To a stirred solution of compound I (50 g; 0.26 mol; 1 eq) in ethanol (2L) was added sodium bicarbonate (46 g; 0.53 mol; 2 eq) andchloroacetaldehyde solution (50% aqueous solution, 86 mL; 0.66 mol; 2.5eq) drop wise and the resulting mixture was heated at reflux for 17 h.The mixture was then evaporated to dryness and the pH was adjusted to 7using ice-cold saturated aqueous NaHCO₃ solution and solid NaHCO₃. Theorganic components were extracted from the aqueous layer with ethylacetate (3×1000 mL) and the combined organic layers were washed withbrine, dried over anhydrous sodium sulfate, filtered and the solvent wasremoved in vacuo to obtain a dry residue which was purified by silicagel (230-400 mesh) column chromatography using 10-50% ethylacetate/hexanes as the eluent to afford the title compound (40 g, 71%)as a brown solid. ¹H NMR (DMSO-d₆) δ 8.04 (s, 1H), 7.77 (s, 1H), 7.44(s, 1H), 6.31 (s, 1H), 5.99 (s, 2H). LCMS: m/z=212.0 [M+], 214.0 [M+2],RT=2.55 minutes, (Program P1, Column V).

Step 2: 8-Amino-imidazo[1,2-a]pyridine-6-carboxylic acid methyl ester

To a solution of compound II (10 g; 47 mmol; 1 eq) in methanol (200 mL)was added diisopropylethyl amine (41 mL; 236 mmol; 5 eq) and theresulting mixture was degassed with argon for 5 min. To the mixture wasadded PdCl₂(dppf) (4 g; 4.72 mmol; 0.1 eq) and the resulting solutionwas degassed with argon for another 5 min and then heated in anautoclave at 90° C. at 50 psi carbon monoxide pressure for 16 h. Themixture was filtered through a Celite® pad and the filtrate was washedwith saturated aqueous NaHCO₃ solution, followed by brine. The organiclayer was then dried over anhydrous Na₂SO₄ and evaporated to dryness toobtain a crude material. The crude product was purified by silica gel(100-200 mesh) column chromatography, eluting with 0-10%methanol/dichloromethane as the eluent to obtain the title compound (5g, 55%) as a light brown solid. ¹H NMR (DMSO-d₆) δ 8.57 (s, 1H), 7.97(s, 1H), 7.5135 (s, 1H), 6.67 (s, 1H), 5.86 (s, 2H), 3.84 (s, 3H). LCMS:m/z=191.8 [M+H]⁺, RT=2.03 minutes, (Program P1, Column V).

Step 3:8-[bis-(tert-Butoxycarbonyl)amino]-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester

To a stirred solution of compound III (3 g; 15.6 mmol; 1 eq) in dry THF(200 mL) at 0° C. were added TEA (6.52 mL; 46 mmol; 3 eq), boc anhydride(4.32 mL, 18.8 mmol; 1.2 eq) dropwise and a catalytic amount of DMAP,and the resulting mixture was heated at reflux for 17 h. The mixture wasdiluted with water (300 mL) and the organic components were extractedwith ethyl acetate (3×200 mL). The combined organic layers were washedwith brine, dried over anhydrous sodium sulfate, filtered and thesolvents were removed in vacuo to obtain dry residue which was purifiedby silica gel (230-400 mesh) column chromatography using 10-50% ethylacetate/hexanes as the eluent to afford the title compound (2.9 g, 49%)as a solid. ¹H NMR (DMSO-d₆) δ 9.36 (s, 1H), 8.15 (s, 1H), 7.67 (s, 1H),7.50 (s, 1H), 3.89 (s, 3H), 1.33 (s, 18H). LCMS: m/z=391.8 [M+H]⁺,RT=3.18 minutes, (Program P1, Column Y).

Step 4:3-Bromo-8-[bis-(tert-Butoxycarbonyl)amino]-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester

To a stirred solution of compound IV (2.88 g; 7.3 mmol; 1 eq) in dry THF(80 mL) was added NBS (1.31 g; 7.3 mmol; 1 eq) in portions at 0° C. andthe resulting mixture was stirred for 30 min at 0° C. The temperature ofthe mixture was then slowly raised to 23° C. and the mixture was stirredfor 2 h. The mixture was poured into ice-cold saturated aqueous NaHCO₃solution and the organic components were extracted with ethyl acetate(3×50 mL). The combined organic layers were then washed with brine,dried over anhydrous sodium sulfate, filtered and concentrated in vacuoto obtain a dry residue which was purified by silica gel (230-400 mesh)column chromatography using 10-50% ethyl acetate/hexanes as the eluentto afford the title compound (3.46 g, 100%) as a solid. ¹H NMR (DMSO-d₆)δ 8.79 (s, 1H), 7.88 (s, 1H), 7.68 (s, 1H), 3.93 (s, 3H), 1.34 (s, 18H).LCMS: m/z=469.8 [M+], 471.8 [M+2], RT=3.54 minutes, (Program P1, ColumnY).

Step 5: 8-Amino-3-bromo-imidazo[1,2-a]pyridine-6-carboxylic acid methylester

To a stirring solution of compound V (3.5 g; 7.4 mmol; 1 eq) in methanol(50 mL) at 0° C. was added 4M methanolic HCl (100 mL) dropwise over aperiod of 30 min and the resulting mixture was stirred at 23° C. for 24h. The mixture was poured into ice-cold saturated aqueous NaHCO₃solution and the organic components were extracted with ethyl acetate(3×500 mL). The combined organic layers were washed with brine, driedover anhydrous sodium sulfate, filtered and concentrated in vacuo toobtain the title compound (2 g, 100%) as solid. LCMS: m/z=269.8 [M+],271.8 [M+2], RT=2.91 minutes, (Program P1, Column Y).

Step 6:3-Bromo-8-[1-dimethylamino-ethylideneamino]-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester

A stirring solution of compound VI (0.42 g; 2.19 mmol; 1 eq) in dimethylacetamide dimethyl acetal (1.5 mL) was heated at reflux for 1 h. Themixture was evaporated to dryness to afford the title compound (0.74 g,100%). LCMS: m/z=339.0 [M+], 341.0 [M+2], RT=2.69 minutes, (Program P1,Column W).

Step 7: 3-Bromo-8-(2,5-dimethyl-imidazol-1-yl)-imidazo-[1,2-a]pyridine-6-carboxylic acidmethyl ester

To compound VII (0.73 g; 2.15 mmol; 1 eq) was added aqueous HCl dropwiseat 0° C., followed by propargyl amine (1.18 g; 21.53 mmol; 10 eq) andthe resulting mixture was stirred at 0° C. for 30 min. The temperaturewas then raised to 100° C. and stirred for another 3 h. The mixture wascooled to room temperature and diluted with ice-cold saturated aqueousNaHCO₃ solution and the organic components were extracted with ethylacetate (3×50 mL). The combined organic layers were then washed withbrine, dried over anhydrous sodium sulfate, filtered and concentrated todryness. The crude product was purified by silica gel (230-400 mesh)column chromatography eluting with 0-5% methanol/CH₂Cl₂ to obtain thetitle compound (0.38 g, 51%) as a brown solid. ¹H NMR (CDCl₃) δ 8.99 (s,1H), 7.72 (s, 2H), 6.82 (s, 1H), 4.01 (s, 3H), 2.20 (s, 3H), 2.00 (s,3H). LCMS: m/z=349.0 [M+], 351.0 [M+2], RT=2.79 minutes, (Program P1,Column Y).

Step 8:8-(2,5-Dimethyl-imidazol-1-yl)-3-(5-methyl-thiophen-2-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester

To a stirred dry toluene solution of compound (0.38 g; 1.08 mmol; 1 eq)in a reaction tube was added compound VIa (0.63 g; 1.63 mmol; 1.5 eq)and the resulting mixture was degassed with argon for 5 min. To themixture was added Pd(PPh₃)₄ (0.12 g; 0.1 mmol; 0.1 eq) and degassingwith argon was repeated for an additional 5 min. The reaction tube wassealed and heated at 115° C. for 4 h. The mixture was filtered through aCelite® pad and the filtrate was washed with saturated aqueous NaHCO₃solution, followed by brine. The organic layer was then dried overanhydrous Na₂SO₄, filtered and the solvents were removed in vacuo toobtain a crude material. The crude product was purified by silica gel(230-400 mesh) column chromatography eluting with 0-5% methanol/CH₂Cl₂to obtain the title compound (0.18 g, 46%) as a light brown solid. ¹HNMR (DMSO-d₆) δ 9.09 (s, 1H), 7.89 (s, 1H), 7.74 (s, 1H), 7.43 (d, 1H,J=3 Hz), 7.04 (d, 1H, J=3 Hz), 6.71 (s, 1H), 3.91 (s, 3H), 2.56 (s, 3H),2.10 (s, 3H), 1.96 (s, 3H). LCMS: m/z=366.8 [M+H]⁺, RT=3.04 minutes,(Program P1, Column W).

Step 9:8-(2,5-Dimethyl-imidazol-1-yl)-3-(5-methyl-thiophen-2-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid

To a solution of compound IX (0.18 g, 0.5 mmol, 1 eq) inTHF:methanol:H₂O (15 mL, 3:2:1) at 0° C. was added a solution of lithiumhydroxide monohydrate (0.062 g, 1.5 mmol, 3 eq) in water (1 mL) and theresulting mixture was stirred at 23° C. for 3 h. The solvent was removedunder reduced pressure and the residue was diluted with water andacidified with 1N HCl to adjust the pH to 3. The precipitated solid wascollected by filtration and dried under vacuum to afford the titlecompound (0.15 g, 88%). ¹H NMR (DMSO-d₆) δ 9.83 (s, 1H), 9.09 (s, 1H),7.89 (s, 1H), 7.74 (s, 1H), 7.43 (d, 1H, J=3 Hz), 7.04 (d, 1H, J=3 Hz),6.71 (s, 1H), 2.50 (s, 3H), 2.10 (s, 3H), 1.96 (s, 3H). LCMS: m/z=353.0[M+H]⁺, RT=2.03 minutes, (Program P1, Column Y).

Step 10:8-(2,5-Dimethyl-1H-imidazol-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide

To a stirred solution of compound X (0.07 g, 0.2 mmol, 1 eq) in CH₂Cl₂(5 mL) were added DIPEA (0.1 mL, 0.6 mmol, 3 eq) and HATU (0.092 g, 0.24mmol, 1.2 eq) at 0° C. and the resulting mixture was stirred for 15 min.To the mixture was added C-(6-methyl-pyridin-3-yl)-methylamine (0.048 g,0.30 mmol, 1.5 eq) and the resulting mixture was allowed to stir at 23°C. for another 16 h. From the mixture, solvent was removed in vacuo andthe residue was diluted with EtOAc, washed with saturated aqueous sodiumbicarbonate solution, aqueous ammonium chloride solution and brine. Theorganic layer was dried over anhydrous sodium sulfate, filtered andconcentrated to dryness. The crude product was purified by silica gel(230-400 mesh) column chromatography eluting with 0-5% methanol/CH₂Cl₂to obtain the title compound (0.01 g, 11%) as an off-white solid. ¹H NMR(DMSO-d₆) δ 9.30 (t, 1H, J=6 Hz), 9.11 (s, 1H), 8.44 (s, 1H), 7.85 (d,2H, J=8 Hz), 7.64 (dd, 1H, J=2, 8 Hz), 7.43 (d, 1H, J=3 Hz), 7.21 (d,1H, J=8 Hz), 7.03 (d, 1H, J=3 Hz), 6.71 (s, 1H), 4.48 (d, 2H, J=6 Hz),2.55 (s, 3H), 2.42 (s, 3H), 2.11 (s, 3H), 1.97 (s, 3H). LCMS: m/z=457.2[M+H]⁺, RT=2.96 minutes, (Program P1, Column Y).

Example 3(S)—N-(1-(4H-1,2,4-Triazol-3-yl)ethyl)-8-(3,5-dimethyl-4H-1,2,4-triazol-4-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide

Following the experimental procedure described for Example 2, compoundVI was prepared.

Step 6:3-Bromo-8-(3,5-dimethyl-[1,2,4]triazol-4-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester

A solution of compound VI (0.6 g; 2.22 mmol; 1 eq) in dimethyl acetamidedimethyl acetal (6 mL) was heated at reflux under stirring for 1 h. Themixture was evaporated to dryness and after cooling the residue to 0°C., HCl (1 mL) was added drop wise, followed by acetic acid hydrazide(0.98 g; 13.33 mmol; 6 eq) and the resulting mixture was stirred at 0°C. for 30 min. The temperature was then raised to 130° C. and stirringwas continued for another 2 h. The mixture was cooled to roomtemperature and diluted with ice-cold saturated aqueous NaHCO₃ solutionand the organic components were extracted with ethyl acetate (3×50 mL).The combined organic layers were then washed with brine, dried overanhydrous sodium sulfate and concentrated to dryness. The crude productwas purified by silica gel (230-400 mesh) column chromatography, elutingwith 0-5% methanol/CH₂Cl₂, to obtain the title compound (0.34 g, 44%) asa brown solid. ¹H NMR (DMSO-d₆) δ 8.90 (s, 1H), 8.03 (s, 1H), 7.94 (s,1H), 3.94 (s, 3H), 2.14 (s, 6H). LCMS: m/z=350.0 [M+], 352.0 [M+2],RT=2.42 minutes, (Program P1, Column Y).

Step 7:8-(3,5-Dimethyl-[1,2,4]triazol-4-yl)-3-(5-methyl-thiophen-2-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester

To a stirred dry DMF solution of compound VII (0.34 g; 0.97 mmol; 1 eq)in a reaction tube was added compound VIa (0.57 g; 1.46 mmol; 1.5 eq)and the resulting mixture was degassed with Argon for 5 min. To themixture was added Pd(PPh₃)₄ (0.12 g; 0.09 mmol; 0.1 eq) and degassingwith Argon was repeated for about 5 min, then the reaction tube wassealed and heated at 130° C. for 4 h. The mixture was quenched with icecold water and the organic components were extracted with EtOAc. Theorganic layer was washed with saturated aqueous sodium bicarbonatesolution, aqueous ammonium chloride solution and brine. The organiclayer was dried over anhydrous sodium sulfate, filtered and concentratedto dryness. The crude product was purified by silica gel (100-200 mesh)column chromatography, eluting with 0-5% Methanol/CH₂Cl₂, to obtain thetitle compound (0.29 g, 80%) as an off white solid. LCMS: m/z=368.0[M+H]⁺, RT=2.97 minutes, (Program P1, Column Y).

Step 8:8-(3,5-Dimethyl-[1,2,4]triazol-4-yl)-3-(5-methyl-thiophen-2-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid

To a solution of compound VIII (0.29 g, 0.79 mmol, 1 eq) inTHF:methanol:H₂O (15 mL, 3:2:1) at 0° C. was added a solution of lithiumhydroxide monohydrate (0.1 g, 2.37 mmol, 3 eq) in water (1 mL) and theresulting mixture was stirred at 23° C. for 30 min. The solvent wasremoved under reduced pressure and the residue was diluted with waterand acidified with 1N HCl to adjust the pH to 3 and organic componentswere extracted with EtOAc. The organic layer was dried over anhydroussodium sulfate, filtered, and concentrated to dryness to afford thetitle compound (0.28 g, 99%) as an off white solid. ¹H NMR (DMSO-d₆) δ9.11 (s, 1H), 8.01 (s, 1H), 7.91 (s, 1H), 7.41 (d, 1H, J=4 Hz), 7.03 (m,1H), 2.25 (s, 6H). LCMS: m/z=354.2 [M+H]⁺, RT=2.08 minutes, (Program P1,Column Y).

Step 9:(S)—N-(1-(4H-1,2,4-Triazol-3-yl)ethyl)-8-(3,5-dimethyl-4H-1,2,4-triazol-4-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide

To a stirred solution of compound IX (0.3 g, 0.85 mmol, 1 eq) in DMF (50mL) were added TEA (0.8 mL, 4.25 mmol, 5 eq), T3P (0.4 mL, 1.30 mmol,1.5 eq) and (S)-1-(4H-[1,2,4]triazol-3-yl)-ethylamine hydrochloride(0.15 g, 1.30 mmol, 1.5 eq) at 23° C., then the resulting mixture washeated at 130° C. for 4 h. The mixture was quenched with ice cold waterand the organic components were extracted with EtOAc. The organic layerwas washed with saturated aqueous sodium bicarbonate solution, aqueousammonium chloride solution and brine. The organic layer was dried overanhydrous sodium sulfate, filtered, and concentrated to dryness. Thecrude product was initially purified by silica gel (100-200 mesh) columnchromatography eluting with 0-10% methanol/CH₂Cl₂ and purified bypreparative TLC to obtain the title compound (0.015 g, 4%) as an offwhite solid. ¹H NMR (DMSO-d₆) δ 13.86 (d, 1H, J=2.4 Hz), 9.16 (m, 2H),8.48 (s, 1H), 8.04 (s, 1H), 7.86 (s, 1H), 7.43 (s, 1H), 7.04 (s, 1H),5.33 (m, 1H), 2.55 (s, 3H), 2.20 (s, 6H), 1.55 (m, 3H). LCMS: m/z=448.2[M+H]⁺, RT=2.45 minutes, (Program P1, Column Y).

Example 4(S)—N-(1-(4H-1,2,4-Triazol-3-yl)ethyl)-8-(5-(difluoromethyl)-1H-1,2,3-triazol-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide

Step 1: 6-Bromo-imidazo[1,2-a]pyridin-8-ylamine

To a stirred solution of compound I (50 g; 0.26 mol; 1 eq) in ethanol (2L) was added sodium bicarbonate (46 g; 0.53 mol; 2 eq) andchloroacetaldehyde solution (50% aqueous solution, 86 mL; 0.66 mol; 2.5eq) dropwise and the resulting mixture was heated at reflux for 17 h.The mixture was evaporated to dryness and the pH was adjusted to 7 usingice-cold saturated aqueous NaHCO₃ solution and solid NaHCO₃. The organiccomponents were extracted from the aqueous layer with ethyl acetate(3×1000 mL) and the combined organic layers were washed with brine,dried over anhydrous sodium sulfate, filtered and the solvents wereremoved in vacuo to obtain a dry residue which was purified by silicagel (230-400 mesh) column chromatography using 10-50% ethylacetate/hexanes as the eluent to afford the title compound (40 g, 71%)as a brown solid. ¹H NMR (DMSO-d₆) δ 8.04 (s, 1H), 7.77 (s, 1H), 7.44(s, 1H), 6.31 (s, 1H), 5.99 (s, 2H). LCMS: m/z=212.0 [M+], 214.0 [M+2],RT=2.55 minutes, (Program P1, Column V).

Step 2: 8-Amino-imidazo[1,2-a]pyridine-6-carboxylic acid methyl ester

To a solution of compound II (10 g; 47.2 mmol; 1 eq) in methanol (200mL) was added diisopropylethyl amine (41 mL; 236 mmol; 5 eq) and theresulting solution was degassed with argon for 5 min. To the mixture wasadded PdCl₂(dppf) (4 g; 4.72 mmol; 0.1 eq) and the resulting solutionwas degassed with argon for another 5 min. The solution was then heatedin an autoclave at 90° C. at 50 psi carbon monoxide pressure for 16 h.The mixture was filtered through a Celite® pad and the filtrate waswashed with saturated aqueous NaHCO₃ solution, followed by brine. Theorganic layer was then dried over anhydrous Na₂SO₄, filtered andevaporated to dryness to obtain a crude material. The crude product waspurified by silica gel (100-200 mesh) column chromatography, elutingwith 0-10% methanol/dichloromethane as the eluent to obtain the titlecompound (5 g, 55%) as light brown solid. ¹H NMR (DMSO-d₆) δ 8.57 (s,1H), 7.97 (s, 1H), 7.51 (s, 1H), 6.67 (s, 1H), 5.86 (s, 2H), 3.84 (s,3H). LCMS: m/z=191.8 [M+H]⁺, RT=2.03 minutes, (Program P1, Column V).

Step 3: 8-Azido-imidazo[1,2-a]pyridine-6-carboxylic acid methyl ester

To a stirred solution of compound III (10 g; 52.36 mmol; 1 eq) in dryTHF (600 mL) were added tertiarybutylnitrite (32 mL; 230 mmol; 4.4 eq)dropwise and trimethylsilylazide (16 mL, 115 mmol, 2.2 eq) at 0° C., andthe resulting mixture was stirred at 23° C. for 17 h. The mixture wasevaporated to dryness to obtain a crude material which was purified bysilica gel (100-200 mesh) column chromatography, eluting with 0-50%ethylacetate/hexanes as the eluent to obtain the title compound (9 g,80%) as light brown solid. ¹H NMR (DMSO-d₆) δ 9.17 (s, 1H), 8.19 (s,1H), 7.71 (s, 1H), 7.11 (s, 1H), 3.87 (s, 3H). LCMS: m/z=218.2 [M+H]⁺,RT=2.69 minutes, (Program P1, Column V).

Step 4:8-(5-Difluoromethyl-4-ethoxycarbonyl-[1,2,3]triazol-1-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester

To a stirred solution of DBU (25 mL; 166 mmol; 1.2 eq) in dry DMF:THF (1L; 1:1) was added 4,4-difluoro-3-oxo-butyric acid ethyl ester (22 mL;207 mmol; 1.5 eq) slowly and the resulting mixture was stirred at 23° C.for 30 min. The mixture was then cooled to 0° C. and compound IV (30 g;138.2 mmol; 1 eq) in DMF:THF solution was added dropwise and the mixturewas allowed to stir at 23° C. for 17 h. The mixture was diluted withwater (1 L) and the organic components were extracted with ethyl acetate(3×700 mL). The combined organic layers were washed with brine, driedover anhydrous sodium sulfate, filtered and the solvents were removed invacuo to obtain a dry residue which was chromatographically purified bysilica gel (230-400 mesh) column chromatography using 10-50% ethylacetate/hexanes as the eluent to afford the title compound (32 g, 65%)as solid. ¹H NMR (DMSO-d₆) δ 9.65 (s, 1H), 8.33 (s, 1H), 8.10 (s, 1H),7.74 (s, 1H), 7.46 (m, 1H), 4.43 (q, J=7 Hz, 2H), 3.96 (s, 3H), 1.36 (t,J=7 Hz, 3H). LCMS: m/z=365.8 [M+H]⁺, RT=2.97 minutes, (Program P1,Column Y).

Step 5:3-Bromo-8-(5-difluoromethyl-4-ethoxycarbonyl-[1,2,3]triazol-1-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester

To a stirred solution of compound V (10 g; 27.4 mmol; 1 eq) in dry THF(150 mL) at 0° C. was added NBS (7.4 g; 41.1 mmol; 1.5 eq) in portionsand the resulting mixture was stirred at 0° C. for 30 min. The mixturewas poured into ice-cold saturated aqueous NaHCO₃ solution and theorganic components were extracted with ethyl acetate (3×500 mL). Theorganic layer was then washed with brine, dried over anhydrous sodiumsulfate and the solvents were removed in vacuo to obtain a dry residuewhich was chromatographically purified by silica gel (230-400 mesh)gravity column using 10-50% ethyl acetate/hexanes as the eluent toafford the title compound (10 g, 82%) as a solid. ¹H NMR (DMSO-d₆) δ9.00 (s, 1H), 8.27 (s, 1H), 7.96 (s, 1H), 7.44 (m, 1H), 4.43 (q, 2H, J=5Hz), 3.96 (s, 3H), 1.35 (t, 3H, J=7 Hz). LCMS: m/z=443.8 [M+], 445.8[M+2], RT=3.20 minutes, (Program P1, Column Y).

Step 6:3-Bromo-8-(4-carboxy-5-difluoromethyl-[1,2,3]triazol-1-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid

To a solution of compound VI (7 g, 15.8 mmol, 1 eq) in THF:methanol:H₂O(115 mL, 3:2:1) at 0° C. was added a solution of lithium hydroxidemonohydrate (2 g, 47.3 mmol, 3 eq) in water (5 mL) and the resultingmixture was stirred at 23° C. for 3 h. The solvent was removed underreduced pressure and the residue was diluted with water and acidifiedwith 1N HCl to adjust the pH to 3. The precipitated solid was collectedby filtration and dried under vacuum to afford the title compound (5 g,80%). ¹H NMR (DMSO-d₆) δ 14.01 (s, 2H), 8.97 (s, 1H), 8.19 (s, 1H), 7.93(s, 1H), 7.46 (m, 1H). LCMS: m/z=402.0 [M+], 403.8 [M+2], RT=0.84minutes, (Program P1, Column Y).

Step 7:3-Bromo-8-(5-difluoromethyl-[1,2,3]triazol-1-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid

Compound VII (5 g; 12.4 mmol; 1 eq) was heated at 200° C. for 1 h toobtain the title compound (3.5 g; 80%). ¹H NMR (DMSO-d₆) δ 14.01 (s,1H), 8.96 (s, 1H), 8.43 (s, 1H), 8.15 (s, 1H), 7.94 (s, 1H), 7.38 (m,1H). LCMS: m/z=357.8 [M+], 359.8 [M+2], RT=1.71 minutes, (Program P1,Column Y).

Step 8:3-Bromo-8-(5-difluoromethyl-[1,2,3]triazol-1-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid [(S)-1-(4H-[1,2,4]triazol-3-yl)-ethyl]-amide

To a stirred solution of compound VIII (2 g, 5.6 mmol, 1 eq) in DMF (20mL) were added DIPEA (3 mL, 16.8 mmol, 3 eq) and HATU (3.2 g, 8.40 mmol,1.5 eq) at 0° C. and the resulting mixture was stirred for 15 min. Tothe mixture was added (S)-1-(4H-[1,2,4]triazol-3-yl)-ethylaminehydrochloride (0.94 g, 8.40 mmol, 1.2 eq) and the resulting mixture wasallowed to stir at 23° C. for another 16 h. From the mixture, solventwas removed in vacuo and the residue was diluted with EtOAc. The organiclayer was washed with saturated aqueous sodium bicarbonate solution,aqueous ammonium chloride solution and brine. The organic layer wasdried over anhydrous sodium sulfate, filtered and concentrated todryness. The crude product was purified by silica gel (230-400 mesh)column chromatography eluting with 0-5% methanol/CH₂Cl₂ to obtain thetitle compound (1 g, 49%) as brown solid. ¹H NMR (DMSO-d₆) δ 13.94 (d,1H), 9.48 (dd, 1H, J=8 Hz), 9.36 (d, 1H), 8.45 (d, 2H), 8.29 (d, 1H,J=12 Hz), 7.93 (m, 1H), 7.52 (m, 1H), 5.35 (q, 1H, J=8 Hz), 1.55 (d, 3H,J=7 Hz). LCMS: m/z=452.2 [M+], 454.2 [M+2], RT=2.40 minutes, (ProgramP1, Column Y).

Step 9:(S)—N-(1-(4H-1,2,4-Triazol-3-yl)ethyl)-8-(5-(difluoromethyl)-1H-1,2,3-triazol-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide

To a stirred, dry DMF solution of compound IX (0.7 g; 1.55 mmol; 1 eq)in a reaction tube was added compound VIa (0.9 g; 2.32 mmol; 1.5 eq) andthe resulting mixture was degassed with argon for 5 min. To the mixturewas added Pd(PPh₃)₄ (0.2 g; 0.15 mmol; 0.1 eq) and degassing with argonwas repeated for about 5 min. The reaction tube was sealed and heated at115° C. for 4 h. The mixture was filtered through a Celite® pad and thefiltrate was washed with saturated aqueous NaHCO₃ solution, followed bybrine. The organic layer was then dried over anhydrous Na₂SO₄, filteredand solvent was removed in vacuo to obtain a crude material. The crudeproduct was purified by silica gel (230-400 mesh) column chromatographyeluting with 0-5% methanol/CH₂Cl₂ to obtain the title compound (0.29 g,40%) as light brown solid. ¹H NMR (DMSO-d₆) δ 13.56 (s, 1H), 9.20 (s,1H), 9.00 (d, 1H), 8.32 (s, 1H), 8.23 (s, 1H), 7.85 (s, 1H), 7.41 (m,3H), 7.03 (s, 1H), 5.37 (q, 1H), 2.50 (s, 3H), 1.60 (s, 3H). LCMS:m/z=470.2 [M+H]⁺, RT=2.87 minutes, (Program P1, Column Y).

Example 58-(5-(Difluoromethyl)-1H-1,2,3-triazol-1-yl)-3-(5-methyl-1,3,4-thiadiazol-2-yl)-N-((6-methylpyridin-3-yl)methyl)imidazo[1,2-a]pyridine-6-carboxamide

Following the experimental procedure described for Example 4, compoundVIII was prepared.

Step 8:3-Bromo-8-(5-difluoromethyl-[1,2,3]triazol-1-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid (6-methyl-pyridin-3-ylmethyl)-amide

To a stirred solution of compound VIII (1 g, 2.8 mmol, 1 eq) in DMF (10mL) were added DIPEA (5 mL, 26 mmol, 8 eq) and HATU (1.6 g, 4.20 mmol,1.5 eq) at 23° C. and the resulting mixture was stirred for 15 min. Tothe mixture was added C-(6-methyl-pyridin-3-yl)-methylamine (520 mg,4.20 mmol, 1.5 eq) and the resulting mixture was allowed to stir at 23°C. for another 16 h. The mixture was quenched with ice cold water (100mL) and the organic components were extracted with EtOAc (2×400 mL). Theorganic layer was washed with saturated aqueous sodium bicarbonatesolution, aqueous ammonium chloride solution and brine. The organiclayer was dried over anhydrous sodium sulfate, filtered and concentratedto dryness. The crude residue was purified by silica gel (100-200 mesh)column chromatography eluting with 0-4% methanol/CH₂Cl₂ to obtain thetitle compound (0.73 g, 57%) as a brown solid. ¹H NMR (DMSO-d₆) δ 9.51(t, 1H, J=6 Hz), 9.11 (s, 1H), 8.46 (m, 2H), 8.23 (s, 1H), 7.93 (s, 1H),7.65 (dd, 1H, J=8, 2 Hz), 7.39 (t, 1H, J=54 Hz), 7.23 (d, 1H, J=8 Hz),4.52 (d, 2H, J=5.6 Hz), 2.44 (s, 3H). LCMS: m/z=462.0 [M+], 464.2 [M+2],RT=2.80 minutes, (Program P1, Column Y).

Step 9:8-(5-(Difluoromethyl)-1H-1,2,3-triazol-1-yl)-3-(5-methyl-1,3,4-thiadiazol-2-yl)-N-((6-methylpyridin-3-yl)methyl)imidazo[1,2-a]pyridine-6-carboxamide

To a stirred, dry DMF solution of compound IX (50 mg; 0.11 mmol; 1 eq)in a reaction tube were added 2-bromo-5-methyl-[1,3,4]thiadiazole (20mg; 0.11 mmol; 1 eq), hexamethylditin (50 mg; 0.16 mmol; 1.5 eq), andthe resulting mixture was degassed with argon for 5 min. To the mixturewas added Pd(PPh₃)₄ (10 mg; 0.01 mmol; 0.1 eq) and degassing with argonwas repeated for about 5 min, and the reaction tube was sealed thenheated at 130° C. for 2 h. The mixture was quenched with ice cold water(50 mL) and the organic components were extracted with EtOAc (2×150 mL).The combined organic layers were washed with saturated aqueous sodiumbicarbonate solution, aqueous ammonium chloride solution and brine. Theorganic layer was dried over anhydrous sodium sulfate, filtered andconcentrated to dryness. The crude product was initially purified bysilica gel (100-200 mesh) column chromatography eluting with 0-2%methanol/CH₂Cl₂ and further purified using preparative TLC to obtain thetitle compound (20 mg, 13%) as off white solid. ¹H NMR (DMSO-d₆) δ 10.27(s, 1H), 9.47 (t, 1H, J=6 Hz), 8.53 (s, 1H), 8.49 (s, 1H), 8.45 (m, 2H),7.66 (dd, 1H, J=8, 2 Hz), 7.41 (t, 1H, J=53 Hz), 7.23 (d, 1H, J=8 Hz),4.53 (d, 2H, J=6 Hz), 2.84 (s, 3H), 2.44 (s, 3H). LCMS: m/z=482.2[M+H]⁺, RT=2.94 minutes, (Program P1, Column Y).

Example 68-(5-Ethyl-1H-pyrazol-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide

Step 1: 6-Bromo-imidazo[1,2-a]pyridin-8-ylamine

To a stirred solution of compound I (50 g; 0.26 mol; 1 eq) in ethanol (2L) were added sodium bicarbonate (46 g; 0.53 mol; 2 eq) andchloroacetaldehyde solution (50% aqueous solution, 86 mL; 0.66 mol; 2.5eq) drop wise and the resulting mixture was heated at reflux for 17 h.The mixture was then evaporated to dryness and the pH was adjusted to 7using ice-cold saturated aqueous NaHCO₃ solution and solid NaHCO₃. Theorganic components were extracted from the aqueous layer with ethylacetate (3×1000 mL) and the combined organic layers were washed withbrine, dried over anhydrous sodium sulfate and the solvents were removedin vacuo to obtain a dry residue which was purified by silica gel(230-400 mesh) column chromatography using 10-50% ethyl acetate/hexanesas the eluent to afford the title compound (40 g, 71%) as a brown solid.¹H NMR (DMSO-d₆) δ 8.04 (s, 1H), 7.77 (s, 1H), 7.44 (s, 1H), 6.31 (s,1H), 5.99 (s, 2H). LCMS: m/z=212.0 [M+], 214.0 [M+2], RT=2.55 minutes,(Program P1, Column V).

Step 2: 8-Amino-imidazo[1,2-a]pyridine-6-carboxylic acid methyl ester

To a solution of compound II (10 g; 47.2 mmol; 1 eq) in methanol (200mL) was added diisopropylethyl amine (41 mL; 236 mmol; 5 eq) and theresulting mixture was degassed with argon for 5 min. To the mixture wasadded PdCl₂(dppf) (4 g; 4.7 mmol; 0.1 eq) and the resulting mixture wasdegassed with argon for another 5 minutes and then heated in anautoclave at 90° C. at 50 psi carbon monoxide pressure for 16 h. Themixture was filtered through a Celite® pad and the filtrate was washedwith saturated aqueous NaHCO₃ solution, followed by brine. The organiclayer was then dried over anhydrous Na₂SO₄, filtered and evaporated todryness to obtain a crude material. The crude product was purified bysilica gel (100-200 mesh) column chromatography, eluting with 0-10%methanol/dichloromethane as the eluent to obtain the title compound (5g, 55%) as light brown solid. ¹H NMR (DMSO-d₆) δ 8.57 (s, 1H), 7.97 (s,1H), 7.5135 (s, 1H), 6.67 (s, 1H), 5.86 (s, 2H), 3.84 (s, 3H). LCMS:m/z=191.8 [M+H]⁺, RT=2.03 minutes, (Program P1, Column V).

Step 3:8-[bis-(tert-Butoxycarbonyl)amino]-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester

To a stirred solution of compound III (3 g; 15.6 mmol; 1 eq) in dry THF(200 mL) at 0° C. were added TEA (6.52 mL; 46 mmol; 3 eq), boc anhydride(4.32 mL, 18.8 mmol; 1.2 eq) dropwise and a catalytic amount of DMAP,and the resulting mixture was heated at reflux for 17 h. The mixture wasdiluted with water (300 mL) and the organic components were extractedwith ethyl acetate (3×200 mL). The combined organic layers were washedwith brine, dried over anhydrous sodium sulfate, filtered and thesolvents were removed in vacuo to obtain a dry residue which waspurified by silica gel (230-400 mesh) column chromatography using 10-50%ethyl acetate/hexanes as the eluent to afford the title compound (2.9 g,49%) as solid. ¹H NMR (DMSO-d₆) δ 9.36 (s, 1H), 8.15 (s, 1H), 7.67 (s,1H), 7.50 (s, 1H), 3.89 (s, 3H), 1.33 (s, 18H). LCMS: m/z=391.8 [M+H]⁺,RT=3.18 minutes, (Program P1, Column Y).

Step 4:3-Bromo-8-[bis-(tert-Butoxycarbonyl)amino]-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester

To a stirred solution of compound IV (2.88 g; 7.3 mmol; 1 eq) in dry THF(80 mL) was added NBS (1.31 g; 7.3 mmol; 1 eq) in portions at 0° C. andthe resulting mixture was stirred for 30 min at 0° C. The temperature ofthe mixture was then slowly raised to 23° C. and the mixture was stirredfor 2 h. The mixture was poured into ice-cold saturated aqueous NaHCO₃solution and the organic components were extracted with ethyl acetate(3×50 mL). The combined organic layers were then washed with brine,dried over anhydrous sodium sulfate and concentrated in vacuo to obtaina dry residue which was purified by silica gel (230-400 mesh) columnchromatography using 10-50% ethyl acetate/hexanes as the eluent toafford the title compound (3.46 g, 100%) as a solid. ¹H NMR (DMSO-d₆) δ8.79 (s, 1H), 7.88 (s, 1H), 7.68 (s, 1H), 3.93 (s, 3H), 1.34 (s, 18H).LCMS: m/z=469.8 [M+], 471.8 [M+2], RT=3.54 minutes, (Program P1, ColumnY).

Step 5: 8-Amino-3-bromo-imidazo[1,2-a]pyridine-6-carboxylic acid methylester

To a stirring solution of compound V (3.5 g; 7.4 mmol; 1 eq) in methanol(50 mL) at 0° C. was added 4M methanolic HCl (100 mL) dropwise over aperiod of 30 min and the resulting solution was stirred at 23° C. for 24h. The mixture was poured into ice-cold saturated aqueous NaHCO₃solution and the organic components were extracted with ethyl acetate(3×500 mL). The combined organic layers were washed with brine, driedover anhydrous sodium sulfate and concentrated in vacuo to obtain thetitle compound (2 g, 100%) as a solid. LCMS: m/z=269.8 [M+], 271.8[M+2], RT=2.91 minutes, (Program P1, Column Y).

Step 6: 3-Bromo-8-hydrazino-imidazo[1,2-a]pyridine-6-carboxylic acidmethyl ester

To a stirred, cooled (−10° C.) solution of compound VI (0.7 g; 2.5 mmol;1 eq) in concentrated HCl (7 mL) was added an aqueous solution of sodiumnitrite (0.35 g; 5.1 mmol; 2 eq) and the resulting mixture was stirredat −10° C. for 1 h. Tin chloride dehydrate (1.69 g; 7.51 mmol; 3 eq) wasthen added and the resulting mixture was allowed to stir at 23° C. for 1h. The mixture was treated with ice-cold saturated aqueous NaHCO₃solution and solid NaHCO₃ to adjust the pH to 7. The aqueous phase wasextracted with ethyl acetate (3×500 mL) and the combined organic layerswere washed with brine, dried over anhydrous sodium sulfate, filteredand concentrated in vacuo to obtain a dry residue which was purified bysilica gel (230-400 mesh) column chromatography using 10-50% ethylacetate/hexanes as the eluent to afford the title compound (0.3 g, 43%)as an off white solid. LCMS: m/z=285.0 [M+], 286.8 [M+2], RT=2.69minutes, (Program P1, Column Y).

Step 7:3-Bromo-8-(3-ethoxycarbonyl-5-ethyl-pyrazol-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester

To a stirred solution of compound VII (0.3 g; 1 mmol; 1 eq) in ethanolwas added 2-[1-dimethylamino-methylidene]-3-oxo-pentanoic acid ethylester (0.41 g; 2.1 mmol; 2 eq) and the resulting mixture was heated atreflux for 4 h. The mixture was cooled to room temperature, ice-coldsaturated aqueous NaHCO₃ solution was added and the organic componentswere extracted with ethyl acetate (3×50 mL). The combined organic layerswere then washed with brine, dried over anhydrous sodium sulfate andconcentrated to dryness. The crude product was purified by silica gel(230-400 mesh) column chromatography eluting with 0-5% methanol/CH₂Cl₂to obtain the title compound (0.32 g, 73%). LCMS: m/z=421.0 [M+], 423.0[M+2], RT=3.30 minutes, (Program P1, Column Y).

Step 8:8-(3-Ethoxycarbonyl-5-ethyl-pyrazol-1-yl)-3-(5-methyl-thiophen-2-yl)-imidazo[1,2-]pyridine-6-carboxylicacid methyl ester

To a stirred dry DMF solution of compound VIII (0.4 g; 0.91 mmol; 1 eq)in a reaction tube was added compound VIa (0.53 g; 1.3 mmol; 1.5 eq) andthe resulting mixture was degassed with argon for 5 min. To the mixturewas added Pd(PPh₃)₄ (0.1 g; 0.09 mmol; 0.1 eq) and degassing with argonwas repeated for about 5 min. The reaction tube was sealed and heated at115° C. for 4 h. The mixture was filtered through a Celite® pad and thefiltrate was washed with saturated aqueous NaHCO₃ solution, followed bybrine. The organic layer was then dried over anhydrous Na₂SO₄, filteredand solvents were removed in vacuo to obtain a crude material. The crudeproduct was purified by silica gel (230-400 mesh) column chromatographyeluting with 0-50% ethyl acetate/hexane to obtain the title compound(0.25 g, 61%). ¹H NMR (DMSO-d₆) δ 9.12 (s, 1H), 8.09 (s, 1H), 7.90 (s,1H), 7.85 (s, 1H), 7.43 (d, 1H, J=3 Hz), 7.05 (d, 1H), 4.37 (q, 2H, J=7Hz), 4.28 (q, 2H, J=7 Hz), 2.82 (q, 2H, J=1 Hz), 2.56 (s, 3H), 1.30 (m,6H), 1.00 (t, 3H, J=7 Hz). LCMS: m/z=439.0 [M+H]⁺, RT=3.56 minutes,(Program P1, Column Y).

Step 9:8-(3-Carboxy-5-ethyl-pyrazol-1-yl)-3-(5-methyl-thiophen-2-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid

To a solution of compound IX (0.25 g, 0.5 mmol, 1 eq) inTHF:methanol:H₂O (15 mL, 3:2:1) at 0° C. was added a solution of lithiumhydroxide monohydrate (46 mg, 1.1 mmol, 3 eq) in water (1 mL) and theresulting mixture was stirred at 23° C. for 3 h. The solvents wereremoved under reduced pressure and the residue was diluted with waterand acidified with 1N HCl to adjust the pH to 3. The precipitated solidwas collected by filtration and dried under vacuum to afford the titlecompound (0.2 g, 87%). ¹H NMR (DMSO-d₆) δ 9.11 (s, 1H), 8.04 (s, 1H),7.89 (s, 1H), 7.80 (s, 1H), 7.42 (d, 1H, J=3 Hz), 7.03 (d, 1H, J=3 Hz),2.87 (q, 2H, J=7 Hz), 2.56 (s, 3H), 0.88 (t, 3H, J=7 Hz). LCMS:m/z=397.0 [M+H]⁺, RT=1.57 minutes, (Program P1, Column Y).

Step 10:8-(5-Ethyl-pyrazol-1-yl)-3-(5-methyl-thiophen-2-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid

Compound X (0.17 g; 0.42 mmol; 1 eq) was heated at 200° C. for 1 h toobtain the title compound (0.13 g; 86%).

Step 11:8-(5-Ethyl-1H-pyrazol-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide

To a stirred solution of compound XI (0.15 g, 0.42 mmol, 1 eq) inCH₂Cl₂: DMF (1:5, 20 mL) were added DIPEA (0.22 mL, 1.2 mmol, 3 eq) andHATU (0.2 g, 0.54 mmol, 1.3 eq) and the resulting mixture was stirred at0° C. for 15 min. To the mixture was addedC-(6-methyl-pyridin-3-yl)-methylamine (0.13 g, 0.85 mmol, 2 eq) and theresulting mixture allowed to stir at 23° C. for another 16 h. From themixture, solvent was removed in vacuo, the residue was diluted withEtOAc and washed with saturated aqueous sodium bicarbonate solution,aqueous ammonium chloride solution and brine. The organic layer wasdried over anhydrous sodium sulfate, filtered and concentrated todryness. The crude product was purified by silica gel (230-400 mesh)column chromatography eluting with 0-10% methanol/CH₂Cl₂ to obtain thetitle compound (30 mg, 16%) as an off white solid. ¹H NMR (DMSO-d₆) δ9.37 (t, 1H, J=6 Hz), 9.10 (d, 1H, J=1 Hz), 8.42 (d, 1H, J=2 Hz), 7.90(d, 1H, J=1 Hz), 7.84 (s, 1H), 7.68 (d, 1H, J=1 Hz), 7.63 (dd, 1H, J=2,8 Hz), 7.43 (d, 1H, J=4 Hz), 7.22 (d, 1H, J=8 Hz), 7.03 (d, 1H, J=3 Hz),6.35 (s, 1H), 4.48 (d, 2H, J=6 Hz), 2.62 (q, 2H, J=8 Hz), 2.55 (s, 3H),2.50 (s, 3H), 1.11 (t, 3H, J=8 Hz). LCMS: m/z=457.0 [M+H]⁺, RT=3.21minutes, (Program P1, Column Y).

Example 7(S)—N-(1-(4H-1,2,4-Triazol-3-yl)ethyl)-3-(5-methylthiophen-2-yl)-8-(phenylamino)imidazo[1,2-a]pyridine-6-carboxamide

Step 1: 6-Amino-nicotinic acid ethyl ester

To a stirred solution of compound I (150 g; 108.5 mmol; 1 eq) in ethanol(1.5 L) was added thionyl chloride (236 mL; 325 mmol; 3 eq) dropwise at60° C. and the resulting mixture was heated at reflux for 17 h. Themixture was evaporated to dryness and the pH was adjusted to 7, usingice-cold saturated aqueous NaHCO₃ solution and solid NaHCO₃. The organiccomponents were extracted from the aqueous phase with ethyl acetate(3×500 mL), and the combined organic layers were washed with brine,dried over anhydrous sodium sulfate and the solvent was removed in vacuoto afford the title compound (152 g, 84%) as an off-white solid. ¹H NMR(CDCl₃) δ 8.71 (s, 1H), 7.99 (d, 1H, J=12 Hz), 6.45 (d, 1H, J=8 Hz),4.95 (s, 2H), 4.31 (q, 2H, J=8 Hz); 1.35 (t, 3H, J=8 Hz). LCMS:m/z=167.3 [M+H]⁺, RT=2.32 minutes, (Program P1, Column Y).

Step 2: 6-Amino-5-iodo-nicotinic acid ethyl ester

To a stirred solution of iodine (55 g, 219 mmol, 1.4 eq) in ethanol (1L) was added silver sulfate (48.7 g, 312 mmol, 2 eq) and after 5 min,compound II (26 g; 156.4 mmol; 1 eq) was added and the resulting mixturewas stirred at 23° C. for 24 h. The mixture was evaporated to drynessand diluted with 20% aqueous sodium thiosulfate solution. The organiccomponents were extracted from the aqueous phase with ethyl acetate(3×1000 mL) and the combined organic layers were washed with brine,dried over anhydrous sodium sulfate and the solvents were removed invacuo to afford the title compound (45 g, 100%) as a brown solid.

Step 3: 8-Iodo-imidazo[1,2-a]pyridine-6-carboxylic acid ethyl ester

To a stirred solution of compound III (45 g; 154 mmol; 1 eq) in ethanol(2 L) were added sodium bicarbonate (25.9 g; 308 mmol; 2 eq) andchloroacetaldehyde solution (50% aqueous solution, 121 mL; 770 mmol; 5eq) dropwise and the resulting mixture was heated at reflux for 18 h.The mixture was then evaporated to dryness and the pH was adjusted to 7using ice-cold saturated aqueous NaHCO₃ solution and solid NaHCO₃. Theorganic components were extracted from the aqueous phase with ethylacetate (3×500 mL) and the combined organic layers were washed withbrine, dried over anhydrous sodium sulfate and the solvents were removedin vacuo to obtain a dry residue which was purified by silica gel(230-400 mesh) column chromatography using 10-50% ethyl acetate/hexanesas the eluent to afford the title compound (40 g, 83%) as a brown solid.¹H NMR (DMSO-d₆) δ 9.34 (s, 1H), 8.27 (s, 1H), 8.05 (s, 1H), 7.71 (s,1H), 4.35 (q, 2H, J=7 Hz), 1.34 (t, 3H, J=7 Hz). LCMS: m/z=317.0 [M+H]⁺,RT=2.96 minutes, (Program P1, Column Y).

Step 4: 3-Bromo-8-iodo-imidazo[1,2-a]pyridine-6-carboxylic acid ethylester

To a stirred solution of compound IV (30 g; 95 mmol; 1 eq) in dry THF(200 mL) at 0° C. was added NBS (16.8 g; 94.9 mmol; 1 eq) in portionsand the resulting mixture was stirred at 23° C. for 1 h. The mixture waspoured into ice-cold saturated NaHCO₃ aqueous solution and the organiccomponents were extracted with ethyl acetate (3×500 mL). The combinedorganic layers then washed with brine, dried over anhydrous sodiumsulfate, filtered and the solvents were removed in vacuo to obtain a dryresidue. The crude material was purified by silica gel (230-400 mesh)column chromatography using 10-50% ethyl acetate/hexanes as the eluentto afford the compound (38 g, 100%) as a brown solid. ¹H NMR (DMSO-d₆) δ8.75 (s, 1H), 8.16 (s, 1H), 7.93 (s, 1H), 4.39 (q, 2H, J=7 Hz), 1.36 (t,3H, J=7 Hz). LCMS: m/z=395.0 [M+], 397.0 [M+2], RT=3.35 minutes,(Program P1, Column Y).

Step 5: 3-Bromo-8-phenylamino-imidazo[1,2-a]pyridine-6-carboxylic acidethyl ester

To a stirred 1,4-dioxane solution of compound V (1 g; 2.55 mmol; 1 eq)in a reaction tube were added aniline (280 mg; 3.03 mmol; 1.2 eq) andthe resulting mixture was degassed with argon for 5 min, followed by anaddition of K₂CO₃ (1.05 g; 7.59 mmol; 3 eq), Pd(OAc)₂ (57 mg; 0.25 mmol;0.1 eq), xantphos (0.46 g; 0.51 mmol; 0.2 eq). The mixture was thendegassed again with argon for 5 min, the reaction tube was sealed andheated at 110° C. for 5 h. The mixture was filtered through a Celite®pad and the filtrate was washed with saturated aqueous NaHCO₃ solution,followed by brine. The organic layer was then dried over anhydrousNa₂SO₄ and evaporated to dryness to obtain a crude material. The crudeproduct was purified by silica gel (100-200 mesh) column chromatography,eluting with 5-30% EtOAc/hexanes to obtain the title compound (1.5 g,82%). LCMS: m/z=360.2 [M+], 362.0 [M+2], RT=3.84 minutes, (Program P1,Column W).

Step 6:3-(5-Methyl-thiophen-2-yl)-8-phenylamino-imidazo[1,2-a]pyridine-6-carboxylicacid ethyl ester

To a stirred dry toluene solution of compound VI (0.75 g; 2.1 mmol; 1eq) in a reaction tube was added compound VIa (0.96 g; 2.5 mmol; 1.2 eq)and the resulting mixture was degassed with argon for 5 min. To themixture was added Pd(PPh₃)₄ (0.24 g; 0.21 mmol; 0.1 eq) and theresulting mixture was degassed with argon for an additional 5 min. Thereaction tube was sealed and heated at 115° C. for 4 h. The mixture wasfiltered through a Celite® pad and the filtrate was washed withsaturated aqueous NaHCO₃ solution, followed by brine, and the organiclayer was dried over anhydrous Na₂SO₄, filtered and evaporated todryness to obtain a crude material. The crude product was purified bysilica gel (230-400 mesh) column chromatography eluting with 50%EtOAc/hexanes to obtain the title compound (0.48 g, 61%) as a lightbrown solid. ¹H NMR (CDCl₃) δ 8.63 (s, 1H), 7.63 (s, 1H), 7.42 (m, 1H),7.38 (d, 2H, J=7 Hz), 7.34 (d, 2H, J=8 Hz), 7.20 (m, 1H), 6.86 (m, 1H),6.68 (d, 2H, J=8 Hz), 4.38 (q, 2H, J=7 Hz), 2.57 (s, 3H) 1.37 (t, 3H,J=7 Hz). LCMS: m/z=378.2 [M+H]⁺, RT=4.20 minutes, (Program P1, ColumnW).

Step 7:3-(5-Methyl-thiophen-2-yl)-8-phenylamino-imidazo[1,2-a]pyridine-6-carboxylicacid

To a solution of compound VII (0.48 g, 1.27 mmol, 1 eq) inTHF:methanol:H₂O (12 mL, 3:2:1) at 0° C. was added a solution of lithiumhydroxide monohydrate (0.161 g, 3.81 mmol, 3 eq) in water (1 mL) and theresulting mixture was stirred at 23° C. for 3 h. The solvent was removedunder reduced pressure and the residue was diluted with water, acidifiedwith 1N HCl to adjust the pH to 3. The precipitated solid was collectedby filtration and dried under vacuum to afford the title compound (0.38g, 86%). ¹H NMR (DMSO-d₆) δ 8.44 (s, 1H), 8.26 (s, 1H), 7.69 (s, 1H),7.41 (m, 1H), 7.35 (m, 4H), 7.23 (d, 1H, J=4 Hz), 6.98 (m, 2H), 2.54 (s,3H). LCMS: m/z=350.0 [M+H]⁺, RT=2.71 minutes, (Program P1, Column W).

Step 8:(S)—N-(1-(4H-1,2,4-Triazol-3-yl)ethyl)-3-(5-methylthiophen-2-yl)-8-(phenylamino)imidazo[1,2-a]pyridine-6-carboxamide

To a stirred solution of compound VIII (0.38 g, 1.1 mmol, 1 eq) in DMF(10 mL) were added DIPEA (0.6 mL, 3.3 mmol, 3 eq) and HATU (0.49 g, 1.3mmol, 1.2 eq) at 0° C. and the resulting mixture was allowed to stir for15 min. To the mixture was added(S)-1-(4H-[1,2,4]triazol-3-yl)-ethylamine hydrochloride (0.48 g, 3.3mmol, 3 eq) and the resulting mixture was allowed to stir at 23° C. foranother 16 h. From the mixture, solvent was removed in vacuo and theresidue was diluted with EtOAc and then washed with saturated aqueoussodium bicarbonate solution, aqueous ammonium chloride solution andbrine. The organic phase was dried over anhydrous sodium sulfate,filtered and concentrated to dryness. The crude product was purified bysilica gel (230-400 mesh) column chromatography eluting with 0-5%methanol/CH₂Cl₂ to obtain the title compound (0.18 g, 38%) as brownsolid. ¹H NMR (DMSO-d₆) δ 13.78 (m, 1H), 9.14-9.00 (m, 1H), 8.50 (m,3H), 7.86 (s, 1H), 7.40 (d, 1H, J=6 Hz), 7.35 (m, 6H), 7.01 (m, 2H),5.29 (m, 1H), 2.54 (s, 3H), 1.53 (m, 3H). LCMS: m/z=444.0 [M+H]⁺,RT=3.00 minutes, (Program P1, Column Y).

Example 8(S)—N-(1-(4H-1,2,4-Triazol-3-yl)ethyl)-8-(1-methyl-1H-pyrazol-4-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide

Step 1: 6-Amino-nicotinic acid ethyl ester

To a stirred solution of compound I (150 g; 108.5 mmol; 1 eq) in ethanol(1.5 L) at 60° C., was added thionyl chloride (236 mL; 325 mmol; 3 eq)dropwise and the resulting mixture was heated at reflux for 17 h. Themixture was evaporated to dryness and the pH was adjusted to 7 usingice-cold saturated aqueous NaHCO₃ solution and solid NaHCO₃. The organiccomponents were extracted from the aqueous phase with ethyl acetate(5×1000 mL) and the organic layer was washed with brine, dried overanhydrous sodium sulfate, filtered and the solvent was removed in vacuoto afford the title compound (152 g, 84%) as an off-white solid. ¹H NMR(CDCl₃) δ 8.71 (s, 1H), 7.99 (d, 1H, J=12 Hz), 6.45 (d, 1H, J=8 Hz),4.95 (s, 2H), 4.31 (q, 2H, J=8 Hz), 1.35 (t, 3H, J=8 Hz). LCMS:m/z=167.3 [M+H]⁺, RT=2.32 minutes, (Program P1, Column Y).

Step 2: 6-Amino-5-bromo-nicotinic acid ethyl ester

To a stirred solution of compound II (50 g; 30.1 mmol; 1 eq) in dry THF(500 mL) at 0° C. was added NBS (53.6 g; 30.1 mmol; 1 eq) in portionsand the resulting mixture was stirred at 23° C. for 17 h. The mixturewas poured into ice-cold saturated aqueous NaHCO₃ solution and theorganic components were extracted with ethyl acetate (3×1000 mL). Thecombined organic layers were then washed with brine, dried overanhydrous sodium sulfate and evaporated to dryness to afford the titlecompound (71 g, 96%) as an off white solid. ¹H NMR (DMSO-d₆) δ 8.49 (s,1H), 8.07 (s, 1H), 7.15 (s, 2H), 4.22 (q, 2H, J=8 Hz), 1.30 (t, 3H, J=8Hz). LCMS: m/z=245 [M+], 247 [M+2], RT=2.97 minutes, (Program P1, ColumnW).

Step 3: 8-Bromo-imidazo[1,2-a]pyridine-6-carboxylic acid ethyl ester

To a stirred solution of compound III (80 g; 32.6 mmol; 1 eq) in ethanol(1 L) were added sodium bicarbonate (54.83 g; 65.2 mmol; 2 eq) andchloroacetaldehyde solution (˜50% aqueous solution, 212 mL; 163.2 mmol;5 eq) dropwise and the resulting mixture was heated at reflux for 17 h.The mixture was then evaporated to dryness and the pH was adjusted to 7using ice-cold saturated aqueous NaHCO₃ solution and solid NaHCO₃. Theorganic components were extracted from the aqueous phase with ethylacetate (3×500 mL) and the organic layer was washed with brine, driedover anhydrous sodium sulfate, filtered and the solvent was removed invacuo to obtain a dry residue which was purified by silica gel (230-400mesh) column chromatography using 10-50% ethyl acetate/hexanes as theeluent to afford the title compound (55 g, 63%) as a brown solid. ¹H NMR(DMSO-d₆) δ 9.33 (s, 1H), 8.24 (s, 1H), 7.84 (s, 1H), 7.73 (s, 1H), 4.34(q, 2H, J=8 Hz), 1.34 (t, 3H, J=8 Hz). LCMS: m/z=268.8 [M+], 270.8[M+2], RT=2.90 minutes, (Program P1, Column W).

Step 4: 8-(1-Methyl-1H-pyrazol-4-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid ethyl ester

To a stirred solution of compound IV (1 g; 3.73 mmol; 1 eq) intoluene:ethanol (20 mL; 7:3) in a reaction tube was added1-methyl-4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-1H-pyrazole(0.93 g; 4.47 mmol; 1.2 eq) and the resulting solution was degassed withargon for 5 min, followed by addition of Cs₂CO₃ (3.03 g; 9.32 mmol; 2.5eq), Pd(PPh₃)₄ (0.43 g; 0.37 mmol; 0.1 eq). The mixture was thendegassed again with argon for 5 min, the reaction tube was then sealedand heated at 115° C. for 3 h. The mixture was filtered through aCelite® pad and the filtrate was washed with saturated aqueous NaHCO₃solution, followed by brine. The organic layer was then dried overanhydrous Na₂SO₄, filtered and evaporated to dryness to obtain a crudematerial. The crude product was purified by silica gel (100-200 mesh)column chromatography, eluting with 50% EtOAc/hexanes to obtain compoundthe title compound (1.2 g, 60%). ¹H NMR (CDCl₃) δ 8.79 (s, 1H), 8.62 (s,1H), 8.12 (s, 1H), 7.90 (s, 1H), 7.69 (s, 1H), 7.66 (s, 1H), 4.40 (q,2H, J=7 Hz), 3.98 (s, 3H), 1.40 (t, 3H, J=7 Hz). LCMS: m/z=271.0 [M+H]⁺,RT=2.83 minutes, (Program P1, Column W).

Step 5:3-Bromo-8-(1-methyl-1H-pyrazol-4-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid ethyl ester

To a stirred solution of compound V (0.8 g; 2.90 mmol; 1 eq) in dry THF(20 mL) at 0° C. was added NBS (520 mg; 2.9 mmol; 1 eq) in portions andthe resulting mixture was stirred at 0° C. for 30 min. The mixture waspoured into ice-cold saturated aqueous NaHCO₃ solution and the organiccomponents were extracted with ethyl acetate (3×50 mL). The combinedorganic layers were then washed with brine, dried over anhydrous sodiumsulfate and evaporated to dryness to afford the title compound (0.5 g,50%) as an off white solid. ¹H NMR (DMSO-d₆) δ 8.75 (s, 1H), 8.64 (s,1H), 8.36 (s, 1H), 7.97 (s, 1H), 7.93 (s, 1H), 4.40 (q, 2H, J=7 Hz),3.94 (s, 3H), 1.38 (t, 3H, J=7 Hz). LCMS: m/z=349.0 [M+], 351.0 [M+2],RT=3.28 minutes, (Program P1, Column Y).

Step 6:8-(1-Methyl-1H-pyrazol-4-yl)-3-(5-methyl-thiophen-2-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid ethyl ester

To a stirred solution of compound VI (0.5 g; 1.49 mmol; 1 eq) in drytoluene in a reaction tube was added compound VIa (0.63 g; 1.64 mmol;1.1 eq) and the resulting mixture was degassed with argon for 5 min. Tothe mixture was added Pd(PPh₃)₄ (0.17 g; 0.14 mmol; 0.1 eq) and theresulting mixture was degassed with argon again for about 5 min. Thereaction tube was then sealed and heated at 115° C. for 4 h. The mixturewas filtered through a Celite® pad and the filtrate was washed withsaturated aqueous NaHCO₃ solution, followed by brine. The organic layerwas then dried over anhydrous Na₂SO₄, filtered and solvents were removedin vacuo to obtain a crude material. The crude product was purified bysilica gel (230-400 mesh) column chromatography eluting with 50%EtOAc/hexanes to obtain the title compound (0.32 g, 63%). ¹H NMR(DMSO-d₆) δ 8.87 (s, 1H), 8.78 (s, 1H), 8.37 (s, 1H), 7.94 (s, 1H), 7.90(s, 1H), 7.34 (d, 1H, J=4 Hz), 7.02 (d, 1H, J=3 Hz), 4.38 (q, 2H, J=7Hz), 3.95 (s, 3H), 2.56 (s, 3H), 1.35 (t, 3H, J=7 Hz). LCMS: m/z=367.0[M+H]⁺, RT=3.58 minutes, (Program P1, Column Y).

Step 7:8-(1-Methyl-1H-pyrazol-4-yl)-3-(5-methyl-thiophen-2-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid

To a solution of compound VII (0.25 g, 0.68 mmol, 1 eq) inTHF:methanol:H₂O (12 mL, 3:2:1) at 0° C. was added a solution of lithiumhydroxide monohydrate (57 mg, 1.30 mmol, 2 eq) in water (1 mL) and theresulting mixture was stirred at 23° C. for 3 h. The solvent was removedunder reduced pressure and the residue was diluted with water andacidified with 1N HCl to adjust the pH to 3. The precipitated solid wascollected by filtration and dried in vacuo to afford the title compound(0.2 g, 100%). ¹H NMR (DMSO-d₆) δ 8.87 (s, 1H), 8.77 (s, 1H), 8.35 (s,1H), 7.96 (s, 1H), 7.91 (s, 1H), 7.34 (d, 1H, J=4 Hz), 7.01 (d, 1H, J=3Hz), 3.94 (s, 3H), 2.56 (s, 3H). LCMS: m/z=339.0 [M+H]⁺, RT=2.43minutes, (Program P1, Column W).

Step 8:(S)—N-(1-(4H-1,2,4-Triazol-3-yl)ethyl)-8-(1-methyl-1H-pyrazol-4-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide

To a stirred solution of compound VIII (0.2 g, 0.59 mmol, 1 eq) in DMF(10 mL) were added DIPEA (0.3 mL, 1.70 mmol, 3 eq) and HATU (0.26 g,0.71 mmol, 1.2 eq) at 0° C. and the resulting mixture was allowed tostir for 15 min at 23° C. To the mixture was added(S)-1-(4H-[1,2,4]triazol-3-yl)-ethylamine hydrochloride (0.10 g, 0.71mmol, 1.2 eq) and the resulting mixture was stirred at 23° C. foranother 16 h. From the mixture, solvent was removed in vacuo, theresidue was diluted with EtOAc and washed with saturated aqueous sodiumbicarbonate solution, aqueous ammonium chloride solution and brine. Theorganic phase was dried over anhydrous sodium sulfate, filtered andconcentrated to dryness. The crude product was purified by silica gel(230-400 mesh) column chromatography eluting with 0-5% methanol/CH₂Cl₂to obtain the title compound (0.07 g, 30%) as a brown solid. ¹H NMR(DMSO-d₆) δ 13.85 (m, 1H), 9.20 (m, 1H), 8.87 (d, 1H, J=16 Hz), 8.75 (s,1H), 8.49 (s, 1H), 8.34 (s, 1H), 8.16 (d, 1H, J=8 Hz), 7.86 (m, 1H),7.37 (s, 1H), 7.01 (s, 1H), 5.35 (m, 1H), 3.96 (s, 3H), 2.54 (s, 3H),1.58 (m, 3H). LCMS: m/z=433.2 [M+H]⁺, RT=2.78 minutes, (Program P1,Column V).

Example 9(S)—N-(1-(4H-1,2,4-Triazol-3-yl)ethyl)-3-butyl-8-(4-methylpiperidin-1-yl)imidazo[1,2-a]pyridine-6-carboxamide

Step 1: 6-Amino-nicotinic acid ethyl ester

To a stirred solution of compound I (150 g; 1.08 mol; 1 eq) in ethanol(1.5 L) was added thionyl chloride (236 mL; 3.25 mol; 3 eq) dropwise at60° C. and the resulting mixture was heated at reflux for 17 h. Themixture was evaporated to dryness and the pH of the residue was adjustedto 7 using ice-cold saturated aqueous NaHCO₃ solution and solid NaHCO₃.The organic components were extracted from the aqueous phase with ethylacetate (5×1000 mL), and the combined organic layers were washed withbrine solution, dried over anhydrous sodium sulfate, filtered and thesolvent was removed in vacuo to afford the title compound (152 g, 84%)as an off-white solid. ¹H NMR (CDCl₃) δ 8.71 (s, 1H), 7.99 (d, 1H, J=8Hz), 6.45 (d, 1H, J=8 Hz), 4.95 (s, 2H), 4.31 (q, 2H, J=8 Hz); 1.35 (t,3H, J=8 Hz). LCMS: m/z=167.3 [M+H]⁺, RT=2.32 minutes, (Program P1,Column Y).

Step 2: 6-Amino-5-bromo-nicotinic acid ethyl ester

To a stirred solution of compound II (50 g; 301 mmol; 1 eq) in dry THF(500 mL) at 0° C. was added NBS (53.6 g; 301 mmol; 1 eq) in portions andthe mixture was stirred at 23° C. for 17 h. The mixture was poured intoice-cold saturated aqueous NaHCO₃ solution and the organic componentswere extracted from the aqueous phase with ethyl acetate (3×1000 mL).The organic layer was then washed with brine, dried over anhydroussodium sulfate, filtered and evaporated to dryness to afford the titlecompound (71 g, 96%) as an off white solid. ¹H NMR (DMSO-d₆) δ 8.49 (s,1H), 8.07 (s, 1H), 7.15 (s, 2H), 4.22 (q, 2H, J=8 Hz), 1.30 (t, J=8 Hz,3H). LCMS: m/z=245 [M+], 247 [M+2], RT=2.97 minutes, (Program P1, ColumnW).

Step 3: 8-Bromo-imidazo[1,2-a]pyridine-6-carboxylic acid ethyl ester

To a stirred solution of compound III (80 g; 326 mmol; 1 eq) in ethanol(1 L) was added sodium bicarbonate (54.8 g; 652 mmol; 2 eq) andchloroacetaldehyde solution (50% aqueous solution, 212 mL; 1.63 mol; 5eq) dropwise and the mixture was heated at reflux for 17 h. The mixturewas then evaporated to dryness and the pH was adjusted to 7 usingsaturated ice-cold aqueous NaHCO₃ solution and solid NaHCO₃. The organiccomponents were extracted from the aqueous phase with ethyl acetate(3×1000 mL) and the combined organic layers were washed with brine,dried over anhydrous sodium sulfate, filtered and the solvent wasremoved in vacuo to obtain a dry residue which was purified by silicagel (230-400 mesh) column chromatography using 10-50% ethylacetate/hexanes to afford the title compound (55 g, 63%) as a brownsolid. ¹H NMR (DMSO-d₆) δ 9.33 (s, 1H), 8.24 (s, 1H), 7.84 (s, 1H), 7.73(s, 1H), 4.34 (q, 2H, J=8 Hz), 1.34 (t, 3H, J=12 Hz). LCMS: m/z=268.8[M+], 270.8 [M+2], RT=2.90 minutes, (Program P1, Column W).

Step 4: 8-(4-Methyl-piperidin-1-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid ethyl ester

To a stirred 1,4-dioxane solution of compound IV (1 g; 3.71 mmol; 1 eq)in a reaction tube was added 4-methyl piperidine (0.73 g; 7.43 mmol; 2eq) and the resulting mixture was degassed with argon for 5 min,followed by an addition of Cs₂CO₃ (1.81 g; 5.56 mmol; 1.5 eq), Pd₂(dba)₃(0.16 g; 0.018 mmol; 0.05 eq), and xantphos (0.21 g; 0.37 mmol; 0.1 eq).The mixture was then degassed again with argon for 5 min, then thereaction tube was sealed and heated at 115° C. for 5 h. The mixture wasfiltered through a Celite® pad and the filtrate was washed withsaturated aqueous NaHCO₃ solution, followed by brine. The organic layerwas then dried over anhydrous Na₂SO₄ and evaporated to dryness to obtaina crude material. The crude product was purified by silica gel (100-200mesh) column chromatography, eluting with 50% EtOAc/hexanes to obtainthe title compound (0.25 g, 23%) as light brown solid. ¹H NMR (DMSO-d₆)δ 8.84 (s, 1H), 8.03 (s, 1H), 7.55 (s, 1H), 6.75 (s, 1H), 4.31 (m, 4H),2.73 (q, 2H, J=8 Hz), 1.73 (d, 2H, J=12 Hz), 1.56 (m, 1H), 1.3 (m, 5H),0.9 (t, 3H, J=4 Hz). LCMS: m/z=288 [M+H]⁺, RT=3.56 minutes, (Program P1,Column W).

Step 5:3-((E)-But-1-enyl)-8-(4-methyl-piperidin-1-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid ethyl ester

To a stirred solution of compound V (0.15 g; 0.52 mmol; 1 eq) in aceticacid (2 mL) were added sodium acetate (0.17 g; 2 mmol; 4 eq) andbutaraldehyde (0.46 mL; 5.22 mmol; 10 eq) in a sealed tube and themixture was heated at 150° C. for 4 h. The mixture was poured intoice-cold saturated aqueous NaHCO₃ solution and the organic componentswere extracted with ethyl acetate (3×50 mL). The combined organic layerswere washed with brine, dried over anhydrous sodium sulfate, filteredand evaporated to dryness to obtain a crude material. The crude productwas purified by silica gel (230-400 mesh) column chromatography elutingwith 50% EtOAc/hexanes to obtain the title compound (0.12 g, 70%). ¹HNMR (DMSO-d₆) δ 8.60 (s, 1H), 7.75 (s, 1H), 6.90-6.70 (m, 2H), 6.45-6.20(m, 1H), 4.40-4.38 (m, 4H), 2.73 (t, 2H, J=10 Hz), 2.31-2.24 (m, 2H),1.75 (m, 2H), 1.56-1.48 (m, 3H), 1.12 (t, 3H, J=4 Hz), 0.97-0.95 (m,3H), 0.81-0.79 (m, 3H). LCMS: m/z=343.2 [M+H]⁺, RT=2.44 minutes,(Program P1, Column Y).

Step 6:3-Butyl-8-(4-methyl-piperidin-1-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid ethyl ester

To a stirred solution of compound VI (0.12 g; 0.36 mmol; 1 eq) in drymethanol was added 10% Pd/C (40 mg) and the resulting mixture wasstirred under hydrogen atmosphere for 2 h. The mixture was filteredthrough a Celite® pad and the filtrate was evaporated to dryness toobtain the title compound (0.115 g, 92%). ¹H NMR (DMSO-d₆) δ 8.36 (s,1H), 7.36 (s, 1H), 6.77 (s, 1H), 4.40-4.25 (m, 4H), 2.88 (t, 2H, J=8Hz), 2.75 (t, 2H, J=10 Hz), 1.75-1.64 (m, 4H), 1.56 (m, 2H), 1.45-1.38(m, 3H), 1.32 (t, 3H, J=4 Hz), 0.97-0.95 (m, 3H), 0.81-0.79 (m, 3H).LCMS: m/z=344.6 [M+H]⁺, RT=2.55 minutes, (Program P1, Column Y).

Step 7:3-Butyl-8-(4-methyl-piperidin-1-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid

To a solution of compound VII (0.11 g, 0.32 mmol, 1 eq) inTHF:methanol:H₂O (9 mL, 3:2:1) at 0° C. was added a solution of lithiumhydroxide monohydrate (45 mg, 0.96 mmol, 3 eq) in water (0.5 mL) and theresulting mixture was stirred at 23° C. for 3 h. The solvent was removedunder reduced pressure and the residue was diluted with water andacidified with 1N HCl to adjust the pH to 3. The organic components wereextracted from the aqueous phase with ethyl acetate (3×50 mL). Thecombined organic layers were washed with brine, dried over anhydroussodium sulfate, filtered and evaporated to dryness to obtain the titlecompound (0.07 g, 70%). ¹H NMR (DMSO-d₆) δ 8.53 (s, 1H), 7.66 (s, 1H),7.12 (s, 1H), 3.93 (m, 2H), 2.93 (t, 2H, J=15 Hz), 2.75 (t, 2H, J=12Hz), 1.80-1.74 (m, 4H), 1.60 (m, 1H), 1.45-1.32 (m, 4H), 0.97-0.90 (m,6H). LCMS: m/z=316.2 [M+H]⁺, RT=2.60 minutes, (Program P1, Column Y).

Step 8:(S)—N-(1-(4H-1,2,4-Triazol-3-yl)ethyl)-3-butyl-8-(4-methylpiperidin-1-yl)imidazo[1,2-a]pyridine-6-carboxamide

To a stirred solution of compound VIII (40 mg, 0.12 mmol, 1 eq) inCH₂Cl₂ (10 mL) were added DIPEA (0.06 mL, 0.38 mmol, 3 eq) and HATU (58mg, 0.15 mmol, 1.2 eq) at 0° C. and the resulting mixture was allowed tostir for 15 min. To the mixture was added(S)-1-(4H-[1,2,4]triazol-3-yl)-ethylamine hydrochloride (0.022 g, 0.15mmol, 1.2 eq) and the resulting mixture was stirred at 23° C. foranother 16 h. From the mixture, solvent was removed in vacuo, theresidue was diluted with EtOAc and washed with aqueous saturated sodiumbicarbonate solution, aqueous ammonium chloride solution and brine. Theorganic phase was separated, dried over anhydrous sodium sulfate,filtered and concentrated to dryness. The crude product was purified bysilica gel (230-400 mesh) column chromatography eluting with 0-5%methanol/CH₂Cl₂ to obtain the title compound (0.015 g, 30%) as off whitesolid. ¹H NMR (DMSO-d₆) δ 13.83 (m, 1H), 8.86 (m, 1H), 8.44 (m, 2H),7.87 (s, 1H), 7.34 (m, 1H), 6.86 (s, 1H), 5.34 (m, 1H), 4.32 (m, 2H),2.85 (t, 2H, J=7 Hz), 2.71 (t, 2H, J=11 Hz), 1.73 (m, 4H), 1.55 (m, 4H),1.44-1.32 (m, 4H), 0.97-0.90 (m, 6H). LCMS: m/z=409.6 [M+H]⁺, RT=2.60minutes, (Program R1, Column Y).

Example 10(S)—N-(1-(4H-1,2,4-Triazol-3-yl)ethyl)-8-(4-methylpiperidin-1-yl)-3-(propylthio)imidazo[1,2-a]pyridine-6-carboxamide

Step 1: 6-Amino-nicotinic acid ethyl ester

To a stirred solution of compound I (150 g, 1.08 mol; 1 eq) in ethanol(1.5 L) was added thionyl chloride (236 mL; 3.25 mol; 3 eq) dropwise at60° C. and the resulting mixture was heated at reflux for 17 h. Themixture was then evaporated to dryness and the pH of the residue wasadjusted to 7 using ice-cold saturated aqueous NaHCO₃ solution and solidNaHCO₃. The organic components were extracted from the aqueous phasewith ethyl acetate (5×1000 mL) and the combined organic layers werewashed with brine solution, dried over anhydrous sodium sulfate,filtered and the solvent was removed in vacuo to afford the titlecompound (152 g, 84%) as an off-white solid. ¹H NMR (CDCl₃) δ 8.71 (s,1H), 7.99 (d, 1H, J=12 Hz), 6.45 (d, 1H, J=8 Hz), 4.95 (s, 2H), 4.31 (q,2H, J=8 Hz), 1.35 (t, 3H, J=8 Hz). LCMS: m/z=167.3 [M+H]⁺, RT=2.32minutes, (Program P1, Column Y).

Step 2: 6-Amino-5-bromo-nicotinic acid ethyl ester

To a stirred solution of compound II (50 g; 301 mmol; 1 eq) in dry THF(500 mL) at 0° C. was added NBS (53.6 g; 301 mmol; 1 eq) in portions,and the mixture was stirred at 23° C. for 17 h. The mixture was pouredinto ice-cold saturated aqueous NaHCO₃ solution and extracted with ethylacetate (3×1000 mL). The combined organics were then washed with brinesolution, dried over anhydrous sodium sulfate, filtered and evaporatedto dryness to afford the title compound (71 g, 96%) as an off whitesolid. ¹H NMR (DMSO-d₆) δ 8.49 (s, 1H), 8.07 (s, 1H), 7.15 (s, 2H), 4.22(q, 2H, J=8 Hz), 1.30 (t, 3H, J=8 Hz). LCMS: m/z=245 [M+], 247 [M+2],RT=2.97 minutes, (Program P1, Column W).

Step 3: 8-Bromo-imidazo[1,2-a]pyridine-6-carboxylic acid ethyl ester

To a stirred solution of compound III (80 g; 326 mmol; 1 eq) and sodiumbicarbonate (54.83 g; 652 mmol; 2 eq) in ethanol (1 L) was addedchloroacetaldehyde solution (˜50% aqueous solution, 212 mL; 1.6 mol; 5eq) dropwise and the resulting mixture was heated at reflux for 17 h.The mixture was then evaporated to dryness and the pH was adjusted to 7using ice-cold saturated aqueous NaHCO₃ solution and solid NaHCO₃. Theorganic components were extracted from the aqueous phase with ethylacetate (3×1000 mL) and the combined organic layers were washed withbrine, dried over anhydrous sodium sulfate, filtered and the solventswere removed in vacuo to obtain a dry residue which was purified bysilica gel (230-400 mesh) column chromatography using 10-50% ethylacetate/hexanes as the eluent to afford the title compound (55 g, 63%)as a brown solid. ¹H NMR (DMSO-d₆) δ 9.33 (s, 1H), 8.24 (s, 1H), 7.84(s, 1H), 7.73 (s, 1H), 4.34 (q, 2H, J=8 Hz), 1.34 (t, 3H, J=12 Hz).LCMS: m/z=268.8 [M+], 270.8 [M+2], RT=2.90 minutes, (Program P1, ColumnW).

Step 4: 8-(4-Methyl-piperidin-1-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid ethyl ester

To a stirred 1,4-dioxane solution of compound IV (1 g; 3.71 mmol; 1 eq)in a reaction tube was added 4-methyl piperidine (0.73 g; 7.43 mmol; 2eq) and the resulting mixture was degassed with argon for 5 min. To themixture were then added Cs₂CO₃ (1.81 g; 5.56 mmol; 1.5 eq), Pd₂(dba)₃(0.16 g; 0.018 mmol; 0.05 eq), xantphos (0.21 g; 0.37 mmol; 0.1 eq) andthe resulting mixture was degassed with argon for another 5 min and thereaction tube was sealed. The mixture was then heated to 115° C. andstirred for 5 h. The mixture was filtered through a Celite® pad and thefiltrate was washed with saturated aqueous NaHCO₃ solution, followed bybrine. The organic layer was then dried over anhydrous Na₂SO₄ andevaporated to dryness to obtain a crude material. The crude product waspurified by silica gel (100-200 mesh) column chromatography, elutingwith 50% EtOAc/hexanes to obtain the title compound (0.25 g, 23%) aslight brown solid. ¹H NMR (DMSO-d₆) δ 8.84 (s, 1H), 8.03 (s, 1H), 7.55(s, 1H), 6.75 (s, 1H), 4.31 (m, 4H), 2.73 (q, 2H, J=8 Hz), 1.73 (d, 2H,J=12 Hz), 1.56 (m, 1H), 1.3 (m, 5H), 0.9 (t, 3H, J=4 Hz). LCMS: m/z=288[M+H]⁺, RT=3.56 minutes, (Program P1, Column W).

Step 5:3-Bromo-8-(4-methyl-piperidin-1-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid ethyl ester

To a stirred solution of compound V (1.6 g; 5.5 mmol; 1 eq) in dry THF(30 mL) at 0° C. was added NBS (0.99 g; 5.5 mmol; 1 eq) in portions andthe resulting mixture was stirred at 0° C. for 30 min. The mixture waspoured into ice-cold saturated aqueous NaHCO₃ solution and the organiccomponents were extracted with ethyl acetate (3×500 mL). The combinedorganic layers were then washed with brine, dried over anhydrous sodiumsulfate, filtered and evaporated to dryness to afford the title compound(1.7 g, 83%) as an off white solid. ¹H NMR (DMSO-d₆) δ 8.34 (s, 1H),7.75 (s, 1H), 6.87 (s, 1H), 4.35 (m, 4H), 2.79 (q, 2H, J=12 Hz), 1.73(d, 2H, J=12 Hz), 1.58 (s, 1H), 1.3 (m, 5H), 0.95 (t, 3H, J=4 Hz). LCMS:m/z=366.2 [M+], 368.2 [M+2], RT=2.51 minutes, (Program P1, Column W).

Step 6:8-(4-Methyl-piperidin-1-yl)-3-propylsulfanyl-imidazo[1,2-a]pyridine-6-carboxylicacid ethyl ester

To a stirred 1,4-dioxane solution of compound VI (0.15 g; 0.40 mmol; 1eq) in a reaction tube was added propanethiol (73 mg; 0.81 mmol; 2 eq)and the mixture was degassed with argon for 5 min. To the mixture werethen added Cs₂CO₃ (195 mg; 0.6 mmol; 1.5 eq), Pd₂ (dba)₃ (18 mg; 0.02mmol; 0.05 eq), xantphos (23 mg; 0.04 mmol; 0.1 eq), the resultingmixture was degassed with argon for another 5 min and the reaction tubewas sealed. The mixture was then heated to 115° C. and stirred for 5 h.The mixture was filtered through a Celite® pad and the filtrate waswashed with saturated aqueous NaHCO₃ solution, followed by brine. Theorganic layer was then dried over anhydrous Na₂SO₄, filtered andevaporated to dryness to obtain a crude material. The crude product waspurified by silica gel (100-200 mesh) column chromatography, elutingwith 50% EtOAc/hexanes to obtain the title compound (0.14 g, 91%). ¹HNMR (DMSO-d₆) δ 8.63 (s, 1H), 7.80 (s, 1H), 6.89 (s, 1H), 4.37 (q, 2H,J=4 Hz), 4.33 (m, 2H), 2.78 (t, 2H, J=12 Hz), 2.69 (m, 2H), 1.76 (m,2H), 1.60 (m, 1H), 1.42-1.39 (m, 7H), 0.96 (d, 3H, J=6 Hz), 0.83 (t, 3H,J=7 Hz). LCMS: m/z=375.8 [M+H]⁺, RT=2.97 minutes, (Program P1, ColumnW).

Step 7:8-(4-Methyl-piperidin-1-yl)-3-propylsulfanyl-imidazo[1,2-a]pyridine-6-carboxylicacid

To a solution of compound VII (150 mg, 0.41 mmol, 1 eq) inTHF:methanol:H₂O (12 mL, 3:2:1) at 0° C. was added a solution of lithiumhydroxide monohydrate (34 mg, 0.83 mmol, 2 eq) in water (0.5 mL) and theresulting mixture was stirred at 23° C. for 3 h. The solvent was removedunder reduced pressure and the residue was diluted with water andacidified with 1N HCl to adjust the pH to 3. The solid precipitate wascollected by filtration and dried under vacuum to afford the titlecompound (0.11 g, 79%). ¹H NMR (DMSO-d₆) δ 13.30 (s, 1H), 8.63 (s, 1H),7.79 (s, 1H), 6.91 (s, 1H), 4.27 (d, 2H, J=12 Hz), 2.77 (t, 2H, J=8 Hz),2.66 (t, 2H, J=8 Hz), 1.73 (d, 2H, J=12 Hz), 1.58 (m, 1H), 1.40-1.47 (m,2H), 1.35-1.27 (m, 2H), 0.95-0.91 (m, 6H). LCMS: m/z=334 [M+H]⁺, RT=2.64minutes, (Program P1, Column W).

Step 8:(S)—N-(1-(4H-1,2,4-Triazol-3-yl)ethyl)-8-(4-methylpiperidin-1-yl)-3-(propylthio)imidazo[1,2-a]pyridine-6-carboxamide

To a stirred solution of compound VIII (0.05 g, 0.14 mmol, 1 eq) inCH₂Cl₂ (10 mL) was added DIPEA (0.075 mL, 0.42 mmol, 3 eq) and HATU(0.069 g, 0.18 mmol, 1.3 eq) at 0° C. and the resulting mixture wasallowed to stir for 15 min. To the mixture was added(S)-1-(4H-[1,2,4]triazol-3-yl)-ethylamine hydrochloride (0.025 g, 0.17mmol, 1.2 eq) and the resulting mixture was allowed to stir at 23° C.for another 16 h. From the mixture, solvent was removed in vacuo,diluted with EtOAc and washed with saturated aqueous sodium bicarbonatesolution, aqueous ammonium chloride solution and brine. The organiclayer was dried over anhydrous sodium sulfate, filtered and concentratedto dryness to obtain a crude product. The crude material was purified bysilica gel (230-400 mesh) column chromatography eluting with 0-5%methanol/CH₂Cl₂ to obtain the title compound (0.015 g, 23%). ¹H NMR(CDCl₃) δ 11.79 (s, 1H), 8.52 (s, 1H), 8.04 (s, 1H), 7.72 (s, 1H), 6.85(s, 1H), 6.70 (s, 1H), 5.46 (q, 1H, J=8 Hz), 4.19 (d, 2H, J=12 Hz), 2.79(t, 2H, J=12 Hz), 2.56 (t, 2H, J=8 Hz), 1.78 (d, 4H, J=4 Hz), 1.53-1.46(m, 5H), 1.0-0.93 (m, 6H). LCMS: m/z=428.4 [M+H]⁺, RT=3.15 minutes,(Program P1, Column W).

Example 11(S)—N-(1-(4H-1,2,4-Triazol-3-yl)ethyl)-8-(4-methylpiperidin-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide

Step 1: 6-Amino-nicotinic acid ethyl ester

To a stirred solution of compound I (150 g; 1.09 mol; 1 eq) in ethanol(1.5 L) was added thionyl chloride (236 mL; 3.26 mol; 3 eq) dropwise at60° C. and the resulting mixture was heated at reflux for 17 h. Themixture was evaporated to dryness and the pH was adjusted to 7 usingice-cold saturated aqueous NaHCO₃ solution and solid NaHCO₃. The organiccomponents were extracted from the aqueous phase with ethyl acetate(5×1000 mL) and the organic layer was washed with brine, dried overanhydrous sodium sulfate, filtered and the solvent was removed in vacuoto afford the title compound (152 g, 84%) as an off-white solid. ¹H NMR(CDCl₃) δ 8.71 (s, 1H), 7.99 (d, 1H, J=12 Hz), 6.45 (d, 1H, J=8 Hz),4.95 (s, 2H), 4.31 (q, 2H, J=8 Hz), 1.35 (t, 3H, J=12 Hz). LCMS:m/z=167.3 [M+H]⁺, RT=2.32 minutes, (Program P1, Column Y).

Step 2: 6-Amino-5-bromo-nicotinic acid ethyl ester

To a stirred solution of compound II (50 g; 301 mmol; 1 eq) in dry THF(500 mL) at 0° C. was added NBS (53.6 g; 301 mmol; 1 eq) in portions andthe resulting mixture was stirred at 23° C. for 17 h. The mixture waspoured into ice-cold saturated aqueous NaHCO₃ solution and the organiccomponents were extracted with ethyl acetate (3×1000 mL). The combinedorganic layers were then washed with brine solution, dried overanhydrous sodium sulfate, concentrated and evaporated to dryness toafford the title compound (71 g, 96%) as an off white solid. ¹H NMR(DMSO-d₆) δ 8.49 (s, 1H), 8.07 (s, 1H), 7.15 (s, 2H), 4.22 (q, 2H, J=8Hz), 1.30 (t, 3H, J=8 Hz). LCMS: m/z=245 [M+], 247 [M+2], RT=2.97minutes, (Program P1, Column W).

Step 3: 8-Bromo-imidazo[1,2-a]pyridine-6-carboxylic acid ethyl ester

To a stirred solution of compound III (80 g; 326 mmol; 1 eq) in ethanol(1 L) were added sodium bicarbonate (54.8 g; 652 mmol; 2 eq) and aqueouschloroacetaldehyde solution (˜50% aqueous solution, 212 mL; 1.63 mol; 5eq) dropwise and the mixture was heated at refluxed for 17 h. Themixture was then evaporated to dryness and the pH of the residue wasadjusted to 7 using ice-cold saturated aqueous NaHCO₃ solution and solidNaHCO₃. The organic components were extracted from the aqueous phasewith ethyl acetate (3×1000 mL) and the combined organic layers werewashed with brine, dried over anhydrous sodium sulfate and filtered. Thefiltrate was concentrated in vacuo to obtain a dry residue which waspurified by silica gel (230-400 mesh) column chromatography using 10-50%ethyl acetate/hexanes as the eluent to afford the title compound (55 g,63%) as a brown solid. ¹H NMR (DMSO-d₆) δ 9.33 (s, 1H), 8.24 (s, 1H),7.84 (s, 1H), 7.73 (s, 1H), 4.34 (q, 2H, J=8 Hz), 1.34 (t, 3H, J=8 Hz).LCMS: m/z=268.8 [M+], 270.8 [M+2], RT=2.90 minutes, (Program P1, ColumnW).

Step 4: 8-(4-Methyl-piperidin-1-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid ethyl ester

To a stirred 1,4-dioxane solution of compound IV (1 g; 3.71 mmol; 1 eq)in a reaction tube was added 4-methyl piperidine (0.73 g; 7.43 mmol; 2eq) and the resulting mixture was degassed with argon for 5 min,followed by addition of Cs₂CO₃ (1.81 g; 5.56 mmol; 1.5 eq), Pd₂(dba)₃(0.16 g; 0.018 mmol; 0.05 eq) and xantphos (0.21 g; 0.37 mmol; 0.1 eq).The mixture was then degassed again with argon for 5 min, the reactiontube was sealed and heated at 115° C. for 5 h. The mixture was filteredthrough a Celite® pad and the filtrate was washed with saturated aqueousNaHCO₃ solution, followed by brine. The organic layer was then driedover anhydrous Na₂SO₄, filtered and evaporated to dryness to obtain acrude material. The crude product was purified by silica gel (100-200mesh) column chromatography, eluting with 50% EtOAc/hexanes to obtainthe title compound (0.25 g, 23%) as a light brown solid. ¹H NMR(DMSO-d₆) δ 8.84 (s, 1H), 8.03 (s, 1H), 7.55 (s, 1H), 6.75 (s, 1H), 4.31(m, 4H), 2.73 (q, 2H, J=8 Hz), 1.73 (d, 2H, J=12 Hz), 1.56 (m, 1H), 1.3(m, 5H), 0.9 (t, 3H, J=4 Hz). LCMS: m/z=288 [M+H]⁺, RT=3.56 minutes,(Program P1, Column W).

Step 5:3-Bromo-8-(4-methyl-piperidin-1-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid ethyl ester

To a stirred solution of compound (1.6 g; 5.5 mmol; 1 eq) in dry THF (30mL) at 0° C. was added NBS (0.99 g; 5.5 mmol; 1 eq) in portions, and theresulting mixture was stirred at 0° C. for 30 min. The mixture waspoured into ice-cold saturated aqueous NaHCO₃ solution and the organiccomponents were extracted with ethyl acetate (3×500 mL). The combinedorganic layers were then washed with brine solution, dried overanhydrous sodium sulfate, filtered and evaporated to dryness to affordthe title compound (1.7 g, 83%) as an off white solid. ¹H NMR (DMSO-d₆)δ 8.34 (s, 1H), 7.75 (s, 1H), 6.87 (s, 1H), 4.35 (m, 4H), 2.79 (q, 2H,J=12 Hz), 1.73 (d, 2H, J=12 Hz), 1.58 (s, 1H), 1.3 (m, 5H), 0.95 (t, 3H,J=4 Hz). LCMS: m/z=366.2 [M+], 368.2 [M+2], RT=2.51 minutes, (ProgramP1, Column W).

Step 6:8-(4-Methyl-piperidin-1-yl)-3-(5-methyl-thiophen-2-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid ethyl ester

To a stirred solution of compound VI (1 g; 2.7 mmol; 1 eq) in drytoluene in a reaction tube was added compound VIa (1.58 g; 4 mmol; 1.5eq) and the resulting mixture was degassed with argon for 5 min.Pd(PPh₃)₄ (0.31 g; 0.27 mmol; 0.1 eq) was added to the mixture and theresulting mixture was degassed again with argon for 5 min. The reactiontube was sealed and the mixture was heated at 115° C. with stirring for4 h. The mixture was then filtered through a Celite® pad and thefiltrate was washed with saturated aqueous NaHCO₃ solution, followed bybrine. The organic layer was then dried over anhydrous Na₂SO₄, filteredand evaporated to dryness to obtain a crude material. The crude productwas purified by silica gel (230-400 mesh) column chromatography elutingwith 50% EtOAc/hexanes to obtain the title compound (0.8 g, 80%) aslight brown solid. ¹H NMR (DMSO-d₆) δ 8.57 (s, 1H), 7.72 (s, 1H), 7.27(d, 1H, J=4 Hz), 6.98 (d, 1H, J=2 Hz), 6.85 (s, 1H), 4.3 (m, 4H), 2.79(q, 2H, J=12 Hz), 2.53 (s, 3H), 1.75 (d, 2H, J=8 Hz), 1.58 (s, 1H), 1.32(m, 5H), 0.96 (d, 3H). LCMS: m/z=384 [M+H]⁺, RT=4.50 minutes, (ProgramP1, Column Y).

Step 7:8-(4-Methyl-piperidin-1-yl)-3-(5-methyl-thiophen-2-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid

To a solution of compound VII (0.8 g, 2.08 mmol, 1 eq) inTHF:methanol:H₂O (12 mL, 3:2:1) at 0° C. was added a solution of lithiumhydroxide monohydrate (0.175 g, 4.1 mmol, 2 eq) in water (1 mL) and theresulting mixture was stirred at 23° C. for 3 h. The solvents wereremoved under reduced pressure and the residue was diluted with waterand acidified with 1N HCl to adjust the pH to 3. The precipitated solidwas collected by filtration and dried under vacuum to afford the titlecompound (0.74 g, 100%). ¹H NMR (DMSO-d₆) δ 8.55 (s, 1H), 7.68 (s, 1H),7.23 (d, 1H, J=3 Hz), 6.97 (d, 1H, J=2 Hz), 6.94 (s, 1H), 4.27 (d, 2H,J=12 Hz), 2.76 (m, 2H), 2.52 (s, 3H), 1.74 (d, 2H, J=8 Hz), 1.67 (m,1H), 1.37 (m, 2H); 0.96 (m, 3H). LCMS: m/z=356.3 [M+H]⁺, RT=2.69minutes, (Program P1, Column Y).

Step 8:(S)—N-(1-(4H-1,2,4-Triazol-3-yl)ethyl)-8-(4-methylpiperidin-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide

To a stirred solution of compound VIII (0.2 g, 0.56 mmol, 1 eq) in DMF(10 mL) were added DIPEA (0.3 mL, 1.6 mmol, 3 eq) and HATU (0.27 g, 0.72mmol, 1.3 eq) at 0° C. and the resulting mixture was allowed to stir for15 min. To the mixture was added(S)-1-(4H-[1,2,4]triazol-3-yl)-ethylamine hydrochloride (0.1 g, 0.67mmol, 1.2 eq) and the resulting mixture was allowed to stir at 23° C.for another 16 h. From the mixture, solvent was removed in vacuo, theresidue was diluted with EtOAc and washed with saturated aqueous sodiumbicarbonate solution, aqueous ammonium chloride solution and brine. Theorganic layer was dried over anhydrous sodium sulfate, filtered andconcentrated to dryness. The crude product was purified by silica gel(230-400 mesh) column chromatography eluting with 0-5% methanol/CH₂Cl₂to obtain the title compound (0.12 g, 48%) as brown solid. ¹H NMR(CDCl₃) δ 8.46 (s, 1H), 8.00 (s, 1H), 7.62 (s, 1H), 7.04 (d, 1H, J=2Hz), 6.82 (m, 2H), 6.61 (s, 1H), 5.42 (m, 1H), 4.15 (m, 2H), 2.77 (t,2H, J=12 Hz), 2.48 (s, 3H), 1.75 (m, 5H), 1.52 (m, 3H), 0.99 (d, 3H, J=8Hz). LCMS: m/z=450.0 [M+H]⁺, RT=3.20 minutes, (Program P1, Column W).

Example 12(S)—N-(1-(4H-1,2,4-Triazol-3-yl)ethyl)-8-(4-carbamoyl-4-methylpiperidin-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide

Following the experimental procedure described for Example 11, compoundIV was prepared.

Step 4:8-(4-Benzyloxycarbonyl-4-methyl-piperidin-1-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid ethyl ester

To a stirred 1,4-dioxane (40 mL) solution of compound IV (1 g; 3.71mmol; 1 eq) in a reaction tube was added4-methyl-piperidine-4-carboxylic acid benzyl ester (1.5 g; 5.6 mmol; 1.5eq) and the resulting mixture was degassed with argon for 5 min,followed by an addition of Cs₂CO₃ (3.63 g; 11.15 mmol; 3 eq), Pd₂(dba)₃(0.17 g; 0.019 mmol; 0.05 eq) and xantphos (0.21 g; 0.37 mmol; 0.1 eq).The mixture was then degassed again with argon for 5 min, the tube wassealed and heated at 130° C. for 5 h. The mixture was filtered through aCelite® pad, the filtrate was diluted with water (200 mL), and theorganic components were extracted with ethyl acetate (200 mL). Theorganic layer was washed with saturated aqueous NaHCO₃ solution, brineand dried over anhydrous Na₂SO₄ then filtered. The filtrate was thenconcentrated under reduced pressure to obtain a crude material which waspurified by Combiflash™ chromatography, eluting with 50% EtOAc/hexanesto obtain the title compound (0.33 g, 23%) as a light brown solid. ¹HNMR (CDCl₃) δ 8.52 (s, 1H), 7.59 (s, 1H), 7.55 (s, 1H), 7.33 (m, 5H),6.91 (s, 1H), 5.16 (s, 2H), 4.37 (q, 2H, J=7 Hz), 3.92 (m, 2H), 3.06 (t,2H, J=10 Hz), 2.34 (d, 2H, J=14 Hz), 1.77 (m, 2H), 1.39 (t, 3H, J=7 Hz),1.29 (s, 3H). LCMS: m/z=422.2 [M+H]⁺, RT=3.77 minutes, (Program P1,Column W).

Step 5:8-(4-Benzyloxycarbonyl-4-methyl-piperidin-1-yl)-3-bromo-imidazo[1,2-a]pyridine-6-carboxylicacid ethyl ester

To a stirred solution of compound V (1 g; 2.37 mmol; 1 eq) in dry THF(20 mL) at 0° C. was added NBS (0.29 g; 1.66 mmol; 0.7 eq) in portions,and the resulting mixture was stirred at 0° C. for 5 min. The mixturewas poured into ice-cold saturated aqueous NaHCO₃ solution and theorganic components were extracted with ethyl acetate (3×100 mL). Thecombined organic layers were then washed with brine solution, dried overanhydrous sodium sulfate, filtered and evaporated to dryness to affordthe title compound (0.67 g, 56%) as an off white solid. ¹H NMR (CDCl₃) δ8.48 (s, 1H), 7.57 (s, 1H), 7.33 (m, 5H), 6.99 (s, 1H), 5.16 (s, 2H),4.40 (q, 2H, J=7 Hz), 3.90 (m, 2H), 3.06 (t, 2H, J=11 Hz), 2.34 (d, 2H,J=13 Hz), 1.77 (m, 2H), 1.41 (t, 3H, J=7 Hz), 1.29 (s, 3H). LCMS:m/z=500.2 [M+], 502.4 [M+2], RT=4.06 minutes, (Program P1, Column V).

Step 6:8-(4-Benzyloxycarbonyl-4-methyl-piperidin-1-yl)-3-(5-methyl-thiophen-2-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid ethyl ester

To a stirred solution of compound VI (0.67 g; 1.34 mmol; 1 eq) in dryDMF (5 mL) in a reaction tube was added compound VIa (0.66 g; 1.60 mmol;1.2 eq) and the resulting mixture was degassed with argon for 5 minPd(PPh₃)₄ (0.15 g; 0.13 mmol; 0.1 eq) was then added to the mixture anddegassed again with argon for 5 min. The reaction tube was sealed andthe mixture was heated at 140° C. with stirring for 4 h. The mixture wasfiltered through a Celite® pad and the filtrate was diluted with ethylacetate (200 mL) and water (200 mL). The organic layer was washed withwater (200 mL) and brine, then dried over anhydrous Na₂SO₄ and filtered.The filtrate was evaporated under vacuum to obtain a crude materialwhich was purified by Combiflash® chromatography, eluting with 50%EtOAc/hexanes to obtain the title compound (0.65 g, 94%) as a lightbrown solid. ¹H NMR (CDCl₃) δ 8.71 (s, 1H), 7.63 (s, 1H), 7.34 (m, 5H),7.06 (d, 1H, J=4 Hz), 6.96 (s, 1H), 6.84 (d, 1H, J=4 Hz), 5.17 (s, 2H),4.38 (q, 2H, J=7 Hz), 3.92 (m, 2H), 3.07 (t, 2H, J=10 Hz), 2.55 (s, 3H),2.35 (d, 2H, J=14 Hz), 1.77 (m, 2H), 1.38 (t, 3H, J=7 Hz), 1.30 (s, 3H).LCMS: m/z=518.4 [M+H]⁺, RT=4.31 minutes, (Program P1, Column V).

Step 7:8-(4-Carboxy-4-methyl-piperidin-1-yl)-3-(5-methyl-thiophen-2-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid ethyl ester

To a stirred solution of compound VII (0.65 g; 1.25 mmol; 1 eq) in drymethanol was added 10% Pd/C (650 mg) and the resulting mixture wasstirred under hydrogen atmosphere at a pressure for 15 h. The mixturewas filtered through a Celite® pad and the filtrate was concentrated todryness to obtain the title compound (0.45 g, 85%). ¹H NMR (DMSO-d₆) δ8.58 (s, 1H), 7.74 (s, 1H), 7.28 (d, 1H, J=3 Hz), 7.00 (m, 1H), 6.87 (s,1H), 4.32 (q, 2H, J=7 Hz), 4.15 (m, 1H), 3.92 (m, 2H), 2.87 (t, 2H, J=7Hz), 2.54 (s, 3H), 2.33 (m, 2H), 1.70 (m, 2H), 1.37 (m, 3H), 1.30 (s,3H). LCMS: m/z=428.2 [M+H]⁺, RT=2.96 minutes, (Program P1, Column W).

Step 8:8-(4-Carbamoyl-4-methyl-piperidin-1-yl)-3-(5-methyl-thiophen-2-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid ethyl ester

To a stirred solution of compound VIII (0.45 g, 1.05 mmol, 1 eq) in DMF(5 mL) were added DIPEA (0.54 mL, 3.16 mmol, 3 eq) and HATU (0.48 g,1.26 mmol, 1.2 eq) at 0° C. and the resulting mixture was stirred for 15min. To the mixture was added ammonium chloride (0.17 g, 3.16 mmol, 3eq) and the resulting mixture was allowed to stir at 23° C. for another18 h. The mixture was quenched with water and the organic componentswere extracted with ethyl acetate (3×100 mL) and washed with brine. Thecombined organic layers were dried over anhydrous sodium sulfate,filtered and concentrated to dryness to obtain a crude material whichwas purified by Combiflash™ chromatography, eluting with 0-5%methanol/CH₂Cl₂, to obtain the title compound (0.28 g, 63%) as a brownsolid. ¹H NMR (DMSO-d₆) δ 8.57 (s, 1H), 7.73 (s, 1H), 7.28 (d, 1H, J=4Hz), 7.24 (m, 1H), 7.00 (m, 1H), 6.91 (brs, 1H), 6.85 (s, 1H), 4.33 (q,J=11 Hz, 2H), 3.87 (m, 2H), 3.20 (t, J=10 Hz, 2H), 2.54 (s, 3H), 2.14(m, 2H), 1.55 (m, 2H), 1.31 (m, 3H), 1.16 (s, 3H). LCMS: m/z=427.2[M+H]⁺, RT=3.27 minutes, (Program P1, Column V).

Step 9:8-(4-Carbamoyl-4-methyl-piperidin-1-yl)-3-(5-methyl-thiophen-2-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid

To a solution of compound IX (0.28 g, 0.9 mmol, 1 eq) inTHF:methanol:H₂O (14 mL, 5:1:1) at 0° C. was added a solution of lithiumhydroxide monohydrate (0.108 g, 2.6 mmol, 3 eq) in water (1 mL) and theresulting mixture was stirred at 23° C. for 2 h. The organic solvent wasremoved under reduced pressure and the residue was diluted with waterand acidified with 6N HCl to adjust the pH to 3. The precipitated solidwas collected by filtration and the solid was dried under vacuum toafford the title compound (0.20 g, 76%). ¹H NMR (DMSO-d₆) δ 8.52 (s,1H), 7.66 (s, 1H), 7.22 (m, 2H), 6.90 (m, 3H), 3.77 (m, 2H), 3.18 (m,2H), 2.53 (s, 3H), 2.15 (m, 2H), 1.55 (m, 2H), 1.16 (s, 3H). LCMS:m/z=399.0 [M+H]⁺, RT=2.08 minutes, (Program P1, Column W).

Step 10:(S)—N-(1-(4H-1,2,4-Triazol-3-yl)ethyl)-8-(4-carbamoyl-4-methylpiperidin-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide

To a stirred solution of compound X (0.1 g, 0.25 mmol, 1 eq) in DMF (5mL) were added TEA (2 mL, 0.4 mmol, 3 eq), a DMF (2 mL) solution of(S)-1-(4H-[1,2,4]triazol-3-yl)-ethylamine hydrochloride (0.06 g, 0.4mmol, 1.5 eq) and T3P (0.2 mL, 0.4 mmol, 1.5 eq) at 23° C. and theresulting mixture was stirred for 16 h. The mixture was quenched withwater and the organic components were extracted with 10%methanol/dichloromethane (2×200 mL). The combined organic layers werewashed with brine, dried over anhydrous sodium sulfate, filtered andconcentrated to dryness. The crude residue was purified by silica gel(100-200 mesh) column chromatography eluting with 0-10% methanol/CH₂Cl₂(at 8% compound started) to obtain the title compound (0.012 g, 10%) asan off white solid. ¹H NMR (DMSO-d₆-80° C.) δ 13.61 (brs, 1H), 8.77 (s,1H), 8.54 (s, 1H), 8.14 (brs, 1H), 7.64 (s, 1H), 7.26 (s, 1H), 6.96 (s,2H), 6.78 (brs, 2H), 5.34 (m, 1H), 3.86 (m, 2H), 3.36 (m, 2H), 2.54 (s,3H), 2.17 (m, 2H), 1.63 (m, 2H), 1.57 (m, 3H), 1.21 (s, 3H). LCMS:m/z=493.4 [M+H]⁺, RT=2.60 minutes, (Program P1, Column V).

Example 138-(4-Carbamoylpiperazin-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide

Compound IXb was synthesized in a similar way as compound IX wasprepared in scheme 28, replacing 4-methyl piperidine with N-BOCpiperazine in step-4 and the triazole amine analog with the pyridineamine analog in step 8. Step-A and Step-B were subsequently carried outto synthesize compound XIb.

Step A:3-(5-Methyl-thiophen-2-yl)-8-piperazin-1-yl-imidazo[1,2-a]pyridine-6-carboxylicacid [(S)-1-(1H-[1,2,4]triazol-3-yl)-ethyl]-amide

To the solution of IXb (240 mg, 0.44 mmol, 1 eq) in CH₂Cl₂ (8 mL) wasadded TFA (0.33 mL, 4.4 mmol, 10 eq) and the resulting mixture wasstirred at 23° C. for 16 h. The mixture was concentrated in vacuo toremove TFA and diluted with water. Aqueous NaHCO₃ was added and theorganic components were extracted with 5% MeOH/CH₂Cl₂. The organic layerwas dried over anhydrous Na₂SO₄, filtered and concentrated under reducedpressure to obtain the title compound (140 mg, 72%) as an off whitesolid. ¹H NMR (DMSO-d₆) δ 9.24 (t, 1H, J=5 Hz), 8.60 (s, 1H), 8.42 (s,1H), 7.69 (s, 1H), 7.62-7.60 (m, 1H), 7.30 (d, 1H, J=3 Hz), 7.21-7.20(m, 1H), 6.99-6.97 (m, 2H), 4.45 (d, 2H, J=5 Hz), 3.57 (s, 4H), 3.02 (s,4H), 2.53 (s, 3H), 2.43 (s, 3H). LCMS: m/z=447.3 [M+H]⁺, RT=2.54minutes, (Program P1, Column V).

Step B:8-(4-Carbamoylpiperazin-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide

To the solution of Xb (80 mg, 0.18 mmol, 1 eq) in THF (5 mL) was addedTMS-isocyanate (0.05 ml, 0.36 mmol, 2 eq) at 23° C. and the resultingmixture was stirred for 4 h. The mixture was then diluted with aqueousNaHCO₃ and the organic components were extracted with 15% MeOH/CH₂Cl₂,dried over anhydrous sodium sulfate, filtered and concentrated underreduced pressure. The crude residue was purified by flash Combiflash™chromatography using 100-200 mesh silica gel eluting with 17%MeOH/CH₂Cl₂ to obtain the title compound (14 mg, 16%) as an off whitesolid. ¹H NMR (DMSO-d₆) δ 9.20 (t, 1H, J=6 Hz), 8.60 (s, 1H), 8.42 (s,1H), 7.70 (s, 1H), 7.62-7.60 (m, 1H), 7.30 (d, 1H, J=3 Hz), 7.22-7.20(m, 1H), 6.98 (m, 2H), 4.46 (d, 2H, J=6 Hz), 3.51 (s, 8H), 2.53 (s, 3H),2.43 (s, 3H). LCMS: m/z=490.2 [M+H]⁺, RT=2.65 minutes, (Program P1,Column W).

Example 14(S)—N-(1-(1,3,4-Oxadiazol-2-yl)ethyl)-8-(5-(difluoromethyl)-1H-1,2,3-triazol-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide

Step 1: 6-Bromo-imidazo[1,2-a]pyridin-8-ylamine

To a stirred solution of compound I (50 g; 0.26 mol; 1 eq) in ethanol (2L) were added sodium bicarbonate (46 g; 0.53 mol; 2 eq) andchloroacetaldehyde solution (50% aqueous solution, 86 mL; 0.66 mol; 2.5eq) dropwise and the resulting mixture was heated at reflux for 17 h.The mixture was evaporated to dryness and the pH was adjusted to 7 usingice-cold saturated aqueous NaHCO₃ solution and solid NaHCO₃. The organiccomponents were extracted from the aqueous phase with ethyl acetate(3×1000 mL) and the combined organic layers were washed with brine,dried over anhydrous sodium sulfate and the solvents were removed invacuo to obtain a dry residue which was purified by silica gel (230-400mesh) column chromatography using 10-50% ethyl acetate/hexanes as theeluent to afford the title compound (40 g, 71%) as a brown solid. ¹H NMR(DMSO-d₆) δ 8.04 (s, 1H), 7.77 (s, 1H), 7.44 (s, 1H), 6.31 (s, 1H), 5.99(s, 2H). LCMS: m/z=212.0 [M+], 214.0 [M+2], RT=2.55 minutes, (ProgramP1, Column V).

Step 2: 8-Amino-imidazo[1,2-a]pyridine-6-carboxylic acid methyl ester

To a solution of compound II (10 g; 47.20 mmol; 1 eq) in methanol (200mL) was added diisopropylethyl amine (41 mL; 236 mmol; 5 eq) and theresulting mixture was degassed with argon for 5 min. To the mixture wasadded PdCl₂(dppf) (4 g; 4.72 mmol; 0.1 eq) and the resulting mixture wasdegassed with argon for another 5 min and then heated in an autoclave at90° C. at 50 psi carbon monoxide pressure for 16 h. The mixture wasfiltered through a Celite® pad and the filtrate was washed withsaturated aqueous NaHCO₃ solution, followed by brine. The organic layerwas then dried over anhydrous Na₂SO₄, filtered and evaporated to drynessto obtain a crude material. The crude product was purified by silica gel(100-200 mesh) column chromatography, eluting with 0-10%methanol/dichloromethane as the eluent to obtain the title compound (5g, 55%) as light brown solid. ¹H NMR (DMSO-d₆) δ 8.57 (s, 1H), 7.97 (s,1H), 7.51 (s, 1H), 6.67 (s, 1H), 5.86 (s, 2H), 3.84 (s, 3H). LCMS:m/z=191.8 [M+H]⁺, RT=2.03 minutes, (Program P1, Column V).

Step 3: 8-Azido-imidazo[1,2-a]pyridine-6-carboxylic acid methyl ester

To a stirred solution of compound III (10 g; 52.36 mmol; 1 eq) in dryTHF (600 mL) were added tertiarybutylnitrite (32 mL; 230 mmol; 4.4 eq)dropwise and trimethylsilylazide (16 mL, 115 mmol, 2.20 eq) at 0° C.,and the resulting mixture was stirred at 23° C. for 17 h. The mixturewas evaporated to dryness to obtain a crude material which was purifiedby silica gel (100-200 mesh) column chromatography, eluting with 0-50%ethylacetate/hexanes as eluent to obtain the title compound (9 g, 80%)as light brown solid. ¹H NMR (DMSO-d₆) δ 9.17 (s, 1H), 8.19 (s, 1H),7.71 (s, 1H), 7.11 (s, 1H), 3.87 (s, 3H). LCMS: m/z=218.2 [M+H]⁺,RT=2.69 minutes, (Program P1, Column V).

Step 4:8-(5-Difluoromethyl-4-ethoxycarbonyl-[1,2,3]triazol-1-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester

To a stirred solution of DBU (25 mL; 166 mmol; 1.2 eq) in dry DMF:THF(1000 mL; 1:1) was added 4,4-difluoro-3-oxo-butyric acid ethyl ester (22mL; 207.3 mmol; 1.5 eq) slowly at 23° C. and the mixture was stirred for30 min. The mixture was then cooled to 0° C. and a DMF:THF (200 ml, 1:1)solution of compound IV (30 g; 138.2 mmol; 1 eq) was added dropwise andthe resulting mixture was allowed to stir at 23° C. for 17 h. Themixture was diluted with water (1000 mL) and the organic components wereextracted with ethyl acetate (3×500 mL). The combined organic layerswere washed with brine, dried over anhydrous sodium sulfate, filteredand the solvent was removed in vacuo to obtain a dry residue which waspurified by silica gel (230-400 mesh) column chromatography using 10-50%ethyl acetate/hexanes as the eluent to afford the title compound (32 g,65%) as a solid. ¹H NMR (DMSO-d₆) δ 9.65 (s, 1H), 8.33 (s, 1H), 8.10 (s,1H), 7.74 (s, 1H), 7.46 (m, 1H), 4.43 (q, 2H, J=7 Hz), 3.96 (s, 3H),1.36 (t, 3H, J=7 Hz). LCMS: m/z=365.8 [M+H]⁺, RT=2.97 minutes, (ProgramP1, Column Y).

Step 5:3-Bromo-8-(5-difluoromethyl-4-ethoxycarbonyl-[1,2,3]triazol-1-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester

To a stirred solution of compound V (10 g; 27.4 mmol; 1 eq) in dry THF(150 mL) at 0° C. was added NBS (7.4 g; 41.1 mmol; 1.5 eq) in portionsand the resulting mixture was stirred at 0° C. for 30 min. The mixturewas poured into ice-cold saturated aqueous NaHCO₃ solution and theorganic components were extracted with ethyl acetate (3×500 mL). Thecombined organic layers were then washed with brine, dried overanhydrous sodium sulfate and the solvents were removed in vacuo toobtain a dry residue which was chromatographically purified by silicagel (230-400 mesh) gravity column using 10-50% ethyl acetate/hexane asthe eluent to afford the title compound (10 g, 82%) as a solid. ¹H NMR(DMSO-d₆) δ 9.00 (s, 1H), 8.27 (s, 1H), 7.96 (s, 1H), 7.44 (m, 1H), 4.43(q, 2H, J=7 Hz), 3.96 (s, 3H), 1.35 (t, 3H, J=7 Hz). LCMS: m/z=443.8[M+], 445.8 [M+2], RT=3.20 minutes, (Program P1, Column Y).

Step 6:8-(5-Difluoromethyl-4-ethoxycarbonyl-[1,2,3]triazol-1-yl)-3-(5-methyl-thiophen-2-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester

To a stirred dry DMF solution of compound VI (0.5 g; 1.13 mmol; 1 eq) ina reaction tube was added compound VIa (0.7 g; 1.70 mmol; 1.5 eq) andthe resulting mixture was degassed with argon for 5 min. To the mixturewas added Pd(PPh₃)₄ (0.13 g; 0.11 mmol; 0.1 eq) and degassing with argonwas repeated for about 5 min. The reaction tube was sealed and heated at115° C. for 4 h. The mixture was filtered through a Celite® pad and thefiltrate was washed with saturated aqueous NaHCO₃ solution, followed bybrine. The organic layer was then dried over anhydrous Na₂SO₄, filteredand solvents were removed in vacuo to obtain a crude material. The crudeproduct was purified by silica gel (230-400 mesh) column chromatographyeluting with 0-5% methanol/CH₂Cl₂ to obtain the title compound (0.25 g,50%) as a light brown solid. ¹H NMR (DMSO-d₆) δ 9.18 (s, 1H), 8.21 (s,1H), 7.93 (s, 1H), 7.47 (m, 2H), 7.05 (s, 1H), 4.44 (q, 2H, J=7 Hz),3.93 (s, 3H), 2.56 (s, 3H), 1.37 (t, 3H, J=7 Hz). LCMS: m/z=461.8[M+H]⁺, RT=3.56 minutes, (Program P1, Column Y).

Step 7:8-(4-Carboxy-5-difluoromethyl-[1,2,3]triazol-1-yl)-3-(5-methyl-thiophen-2-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid

To a solution of compound VII (0.5 g, 1.10 mmol, 1 eq) inTHF:methanol:H₂O (55 mL, 3:2:1) at 0° C. was added a solution of lithiumhydroxide monohydrate (0.14 g, 3.25 mmol, 3 eq) in water (5 mL) and theresulting mixture was stirred at 23° C. for 3 h. The solvents wereremoved under reduced pressure and the residue was diluted with waterand acidified with 1N HCl to adjust the pH to 3. The precipitated solidwas collected by filtration and dried under vacuum to afford the titlecompound (0.35 g, 70%)).

Step 8:8-(5-Difluoromethyl-[1,2,3]triazol-1-yl)-3-(5-methyl-thiophen-2-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid

Compound VIII (0.35 g; 0.83 mmol; 1 eq) was heated at 200° C. for 1 h toobtain the title compound (0.31 g, 95%).

Step 9:N′—((S)-2-{[8-(5-Difluoromethyl-[1,2,3]triazol-1-yl)-3-(5-methyl-thiophen-2-yl)-imidazo[1,2-a]pyridine-6-carbonyl]-amino}-propionyl)-hydrazinecarboxylic acid tert-butyl ester

To a stirred solution of compound IX (0.31 g, 0.83 mmol, 1 eq) in DMF(30 mL) were added DIPEA (0.5 mL, 2.50 mmol, 3 eq) and HATU (0.47 g,1.24 mmol, 1.5 eq) at 0° C. and the resulting mixture was stirred for 15min. To the mixture was added (S)-1-(4H-[1,2,4]triazol-3-yl)-ethylaminehydrochloride (0.25 g, 1.24 mmol, 1.5 eq) and the resulting mixture wasallowed to stir at 23° C. for another 16 h. From the mixture, solventwas removed in vacuo and the residue was diluted with EtOAc. The organiclayer was washed with saturated aqueous sodium bicarbonate solution,aqueous ammonium chloride solution and brine. The organic layer wasdried over anhydrous sodium sulfate, filtered and concentrated todryness. The crude product was purified by silica gel (230-400 mesh)column chromatography eluting with 0-5% methanol/CH₂Cl₂ to obtain thetitle compound (0.3 g, 65%) as a brown solid. ¹H NMR (DMSO-d₆) δ 9.76(s, 1H), 9.21 (s, 1H), 9.07 (d, 1H, J=7 Hz), 8.78 (s, 1H), 8.46 (s, 1H),8.28 (s, 1H), 7.90 (s, 1H), 7.47 (m, 2H), 7.06 (s, 1H), 4.57 (m, 1H),2.56 (s, 3H), 1.37 (m, 12H). LCMS: m/z=561.2 [M+H]⁺, RT=3.20 minutes,(Program P1, Column Y).

Step 10:8-(5-Difluoromethyl-[1,2,3]triazol-1-yl)-3-(5-methyl-thiophen-2-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid ((S)-1-hydrazinocarbonyl-ethyl)-amide

To a stirring solution of compound X (0.3 g; 0.53 mmol; 1 eq) in1,4-dioxane (20 mL) at 0° C. was added 4 M HCl in 1,4-dioxane (10 mL)dropwise over a period of 30 min and the resulting mixture was stirredat 23° C. for 24 h. The volatiles were evaporated in vacuo to obtain thetitle compound (0.2 g, 80%) as a solid. ¹H NMR (DMSO-d₆) δ 11.26 (s,1H), 10.40 (brs, 3H), 9.26 (d, 1H, J=6 Hz), 9.22 (s, 1H), 8.47 (s, 1H),8.29 (s, 1H), 7.93 (s, 1H), 7.47 (m, 2H), 7.06 (s, 1H), 4.57 (m, 1H),2.56 (s, 3H), 1.43 (d, 3H, J=7 Hz). LCMS: m/z=461.4 [M+H]⁺, RT=2.80minutes, (Program P1, Column Y).

Step 11:(S)—N-(1-(1,3,4-Oxadiazol-2-yl)ethyl)-8-(5-(difluoromethyl)-1H-1,2,3-triazol-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide

To a stirring solution of compound XI (0.18 g; 0.40 mmol; 1 eq) inacetic acid (16 mL) at 0° C. was added triethyl orthoformate (0.5 mL,2.40 mmol, 6 eq) dropwise and the resulting mixture was heated at refluxfor 2 h. The mixture was poured into ice-cold saturated aqueous NaHCO₃solution and the organic components were extracted with ethyl acetate(3×50 mL). The combined organic layers were then washed with brine,dried over anhydrous sodium sulfate and concentrated in vacuo to obtaina dry residue which was purified by silica gel (230-400 mesh) columnchromatography using 0-5% methanol/dichloromethane as the eluent toafford the title compound (0.11 g, 60%) as a solid. ¹H NMR (DMSO-d₆) δ9.50 (d, 1H, J=7 Hz), 9.20 (s, 1H), 8.46 (s, 1H), 8.25 (s, 1H), 7.91 (s,1H), 7.45 (m, 3H), 7.05 (d, 1H, J=1 Hz), 5.48 (m, 1H), 2.56 (s, 3H),1.64 (d, 3H, J=7 Hz). LCMS: m/z=471.0 [M+H]⁺, RT=3.08 minutes, (ProgramP1, Column Y).

Example 15(S)—N-(1-(4H-1,2,4-Triazol-3-yl)ethyl)-8-(4-methylpiperidin-1-yl)-3-(o-tolyl)imidazo[1,2-a]pyridine-6-carboxamide

Step 1: 6-Amino-nicotinic acid ethyl ester

To a stirred solution of compound I (150 g; 1.09 mol; 1 eq) in ethanol(1.5 L) was added thionyl chloride (236 mL; 3.26 mol; 3 eq) dropwise at60° C. and the resulting mixture was heated at reflux for 17 h. Themixture was evaporated to dryness and the pH was adjusted to 7 usingice-cold saturated aqueous NaHCO₃ solution and solid NaHCO₃. The organiccomponents were extracted from the aqueous phase with ethyl acetate(5×1000 mL) and the combined organic layers were washed with brine,dried over anhydrous sodium sulfate, filtered and the solvent wasremoved in vacuo to afford the title compound (152 g, 84%) as anoff-white solid. ¹H NMR (CDCl₃) δ 8.71 (s, 1H), 7.99 (d, 1H, J=12 Hz),6.45 (d, 1H, J=8 Hz), 4.95 (s, 2H), 4.31 (q, 2H, J=8 Hz); 1.35 (t, 3H,J=8 Hz). LCMS: m/z=167.3 [M+H]⁺, RT=2.32 minutes, (Program P1, ColumnY).

Step 2: 6-Amino-5-bromo-nicotinic acid ethyl ester

To a stirred solution of compound II (50 g; 301 mmol; 1 eq) in dry THF(500 mL) at 0° C. was added NBS (53.6 g; 301 mmol; 1 eq) in portions andthe resulting mixture was stirred at 23° C. for 17 h. The mixture waspoured into ice-cold saturated aqueous NaHCO₃ solution and the organiccomponents were extracted with ethyl acetate (3×1000 mL). The combinedorganic layers were then washed with brine solution, dried overanhydrous sodium sulfate and evaporated to dryness to afford compound(71 g, 96%) as an off white solid. ¹H NMR (DMSO-d₆) δ 8.49 (s, 1H), 8.07(s, 1H), 7.15 (s, 2H), 4.22 (q, 2H, J=8 Hz), 1.30 (t, 3H, J=8 Hz). LCMS:m/z=245 [M+], 247 [M+2], RT=2.97 minutes, (Program P1, Column W).

Step 3: 8-Bromo-imidazo[1,2-a]pyridine-6-carboxylic acid ethyl ester

To a stirred solution of compound III (80 g; 326 mmol; 1 eq) in ethanol(1 L) were added sodium bicarbonate (54.8 g; 652 mmol; 2 eq) and aqueouschloroacetaldehyde solution (˜50% aqueous solution, 212 mL; 1.63 mol; 5eq) dropwise and the mixture was heated at reflux for 17 h. The mixturewas then evaporated to dryness and the pH was adjusted to 7 usingice-cold saturated aqueous NaHCO₃ solution and solid NaHCO₃. The organiccomponents were extracted from the aqueous phase with ethyl acetate(3×1000 mL) and the combined organic layers were washed with brine,dried over anhydrous sodium sulfate. The solvent from the organic layerwas removed in vacuo to obtain a dry residue which was purified bysilica gel (230-400 mesh) column chromatography using 10-50% ethylacetate/hexanes as the eluent to afford the title compound (55 g, 63%)as a brown solid. ¹H NMR (DMSO-d₆) δ 9.33 (s, 1H), 8.24 (s, 1H), 7.84(s, 1H), 7.73 (s, 1H), 4.34 (q, 2H, J=8 Hz), 1.34 (t, 3H, J=8 Hz). LCMS:m/z=268.8 [M+], 270.8 [M+2], RT=2.90 minutes, (Program P1, Column W).

Step 4: 8-(4-Methyl-piperidin-1-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid ethyl ester

To a stirred 1,4-dioxane solution of compound IV (1 g; 3.71 mmol; 1 eq)in a reaction tube was added 4-methyl piperidine (0.73 g; 7.43 mmol; 2eq) and the resulting mixture was degassed with argon for 5 min,followed by an addition of Cs₂CO₃ (1.81 g; 5.56 mmol; 1.5 eq), Pd₂(dba)₃(0.16 g; 0.018 mmol; 0.05 eq) and xantphos (0.21 g; 0.37 mmol; 0.1 eq).The mixture was then degassed again with argon for 5 min, and thereaction tube was sealed and heated at 115° C. for 5 h. The mixture wasfiltered through a Celite® pad and the filtrate was washed withsaturated aqueous NaHCO₃ solution, followed by brine. The organic layerwas then collected and dried over anhydrous Na₂SO₄, filtered andevaporated to dryness to obtain a crude material. The crude product waspurified by silica gel (100-200 mesh) column chromatography, elutingwith 50% EtOAc/hexanes to obtain the title compound (0.25 g, 23%) as alight brown solid. ¹H NMR (DMSO-d₆) δ 8.84 (s, 1H), 8.03 (s, 1H), 7.55(s, 1H), 6.75 (s, 1H), 4.31 (m, 4H), 2.73 (q, 2H, J=8 Hz), 1.73 (d, 2H,J=12 Hz), 1.56 (m, 1H), 1.3 (m, 5H), 0.9 (t, 3H, J=4 Hz). LCMS: m/z=288[M+H]⁺, RT=3.56 minutes, (Program P1, Column W).

Step 5:3-Bromo-8-(4-methyl-piperidin-1-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid ethyl ester

To a stirred solution of compound V (1.6 g; 5.5 mmol; 1 eq) in dry THF(30 mL) at 0° C. was added NBS (0.99 g; 5.5 mmol; 1 eq) in portions, andthe resulting mixture was stirred at 0° C. for 30 min. The mixture waspoured into ice-cold saturated aqueous NaHCO₃ solution and the organiccomponents were extracted with ethyl acetate (3×500 mL). The combinedorganic layers were then washed with brine solution, dried overanhydrous sodium sulfate and evaporated to dryness to afford the titlecompound (1.7 g, 83%) as an off white solid. ¹H NMR (DMSO-d₆) δ 8.34 (s,1H), 7.75 (s, 1H), 6.87 (s, 1H), 4.35 (m, 4H), 2.79 (q, 2H, J=12 Hz),1.73 (d, 2H, J=12 Hz), 1.58 (s, 1H), 1.3 (m, 5H), 0.95 (t, 3H, J=4 Hz).LCMS: m/z=366.2 [M+], 368.2 [M+2], RT=2.51 minutes, (Program P1, ColumnW).

Step 6:8-(4-Methyl-piperidin-1-yl)-3-o-tolyl-imidazo[1,2-a]pyridine-6-carboxylicacid ethyl ester

To a stirred solution of compound VI (0.6 g; 1.63 mmol; 1 eq) in drytoluene:ethanol (7:3, 20 mL) was added compound VIa (0.33 g; 2.45 mmol;1.5 eq) and the resulting mixture was degassed with argon for 5 min. Tothe mixture was then added Pd(PPh₃)₄ (0.18 g; 0.16 mmol; 0.1 eq), theresulting mixture was degassed with argon for another 5 min, then heatedat 115° C. with stirring for 4 h. The mixture was filtered through aCelite® pad and the filtrate was washed with saturated aqueous NaHCO₃solution, followed by brine. The organic layer was then dried overanhydrous Na₂SO₄, filtered and evaporated to dryness to obtain a crudematerial. The crude product was purified by silica gel (230-400 mesh)column chromatography eluting with 50% EtOAc/hexanes to obtain the titlecompound (0.3 g, 55%) as light brown solid. ¹H NMR (DMSO-d₆) δ 7.93 (s,1H), 7.65 (s, 1H), 7.47 (d, 2H, J=3 Hz), 7.40 (d, 2H, J=3 Hz), 6.83 (s,1H), 4.36 (d, 2H, J=12 Hz), 4.28 (q, 2H, J=7 Hz), 2.81 (t, 2H, J=11 Hz),2.10 (s, 3H), 1.77 (d, 2H, J=12 Hz), 1.60 (m, 1H), 1.36 (m, 2H), 1.25(t, 3H, J=7 Hz), 0.98 (d, 3H, J=6 Hz). LCMS: m/z=378.4 [M+H]⁺, RT=4.11minutes, (Program P1, Column Y).

Step 7:8-(4-Methyl-piperidin-1-yl)-3-o-tolyl-imidazo[1,2-a]pyridine-6-carboxylicacid

To a solution of compound VII (0.34 g, 0.90 mmol, 1 eq) inTHF:methanol:H₂O (12 mL, 3:2:1) at 0° C. was added a solution of lithiumhydroxide monohydrate (0.75 g, 1.80 mmol, 2 eq) in water (1 mL) and theresulting mixture was stirred at 23° C. for 3 h. The solvent was removedunder reduced pressure and the residue was diluted with water and thenacidified with 1N HCl to adjust the pH to 3. The precipitated solid wascollected by filtration and dried in vacuo to obtain the title compound(0.28 g, 88%). ¹H NMR (DMSO-d₆) δ 8.15 (s, 1H), 8.02 (s, 1H), 7.55-7.37(m, 4H), 7.34 (s, 1H), 3.83 (d, 2H, J=11 Hz), 2.86 (t, 2H, J=11 Hz),2.18 (s, 3H), 1.78 (d, 2H, J=12 Hz), 1.62 (m, 1H), 1.48 (m, 2H), 1.00(d, 3H, J=6 Hz). LCMS: m/z=350.0 [M+H]⁺, RT=2.80 minutes, (Program P1,Column Y).

Step 8:(S)—N-(1-(4H-1,2,4-Triazol-3-yl)ethyl)-8-(4-methylpiperidin-1-yl)-3-(o-tolyl)imidazo[1,2-a]pyridine-6-carboxamide

To a stirred solution of compound VIII (0.05 g, 0.14 mmol, 1 eq) inCH₂Cl₂ (10 mL) were added DIPEA (0.07 mL, 0.42 mmol, 3 eq) and HATU(0.06 g, 0.18 mmol, 1.3 eq) at 0° C. and the resulting mixture wasallowed to stir for 15 min. To the mixture was added(S)-1-(4H-[1,2,4]triazol-3-yl)-ethylamine hydrochloride (0.02 g, 0.17mmol, 1.2 eq) and the resulting mixture was allowed to stir at 23° C.for another 16 h. From the mixture, solvent was removed in vacuo, theresidue was diluted with EtOAc and washed with saturated aqueous sodiumbicarbonate solution, aqueous ammonium chloride solution and brine. Theorganic layer was dried over anhydrous sodium sulfate, filtered andconcentrated to dryness. The crude product was purified by silica gel(230-400 mesh) column chromatography eluting with 0-5% methanol/CH₂Cl₂to obtain the title compound (0.02 g, 40%) as a brown solid. ¹H NMR(DMSO-d₆) (100° C.) δ 13.78 (brs, 1H), 8.54 (s, 1H), 7.93 (s, 1H),7.53-7.37 (s, 1H), 7.37 (m, 4H), 6.92 (s, 1H), 5.30 (m, 1H), 4.42 (d,2H, J=12 Hz), 2.88 (t, 2H, J=11 Hz), 1.81 (s, 3H), 1.79 (d, 2H, J=12Hz), 1.55 (m, 1H), 1.43 (d, 3H, J=12 Hz), 1.39 (m, 2H), 1.02 (d, 3H, J=5Hz). LCMS: m/z=444.4 [M+H]⁺, RT=3.03 minutes, (Program P1, Column V).

Example 168-(5-Cyclopropyl-1H-tetrazol-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide

Step 1: tert-Butyl-(3-nitro-pyridin-2-yl)-amine

To a solution of compound I (20 g, 127 mmol, 1 eq) inN-methyl-2-pyrrolidine (100 mL, 1.04 mol, 8.2 eq) was added tert-butylamine (100 mL, 950 mmol, 7.5 eq) and the resulting mixture was stirredat 60° C. for 5 h. The mixture was poured into ice-cold 1N aqueous HClsolution (500 mL) and the organic components were extracted with ethylacetate (3×300 mL). The combined organic layers were washed withsaturated aqueous sodium bicarbonate solution (400 mL) and brine (2×300mL), dried over anhydrous sodium sulfate, filtered and concentratedunder reduced pressure to provide crude compound. The crude product waspurified by silica gel (100-200 mesh) column chromatography using 2%ethyl acetate/hexanes to obtain the title compound (18 g, 73%) as yellowviscous liquid. ¹H NMR (400 MHz, DMSO-d₆) δ 8.48 (dd, 1H, J=1, 4 Hz),8.41 (dd, 1H, J=2, 8 Hz), 8.20 (brs, 1H), 6.76 (dd, 1H, J=4, 8 Hz), 1.51(s, 9H).

Step 2: 2-tert-Butylamino-3-aminopyridine

To a solution of compound II (18 g, 92.3 mmol, 1 eq) in ethanol (300mL), degassed with argon, was added 10% Pd/C (12 g) and the resultingmixture was degassed with argon for another 15 min. The reaction vesselwas attached to Parr shaker and stirred at 50 psi under hydrogenatmosphere for 16 h. The mixture was filtered through a Celite® pad andthe filtrate was concentrated in vacuo to obtain the title compound (13g, 85%) as deep brown solid. ¹H NMR (400 MHz, DMSO-d₆) δ 7.36 (dd, 1H,J=1, 5 Hz), 6.65 (dd, 1H, J=2, 7 Hz), 6.29 (dd, 1H, J=5, 7 Hz), 4.80 (s,1H), 4.66 (s, 2H), 1.41 (s, 9H). LCMS: m/z=166.4 [M+H], RT=0.79 minutes;(Program R1, Column Y).

Step 3: Cyclopropanecarboxylic acid(2-tert-butylamino-pyridin-3-yl)-amide

To a solution of compound III (7 g, 42.4 mmol, 1 eq) in THF (300 mL) at0° C. was added DIPEA (22.2 mL, 127.2 mmol, 3 eq) dropwise and theresulting mixture was stirred for 10 min Cyclopropane carbonyl chloride(3.9 mL, 42.4 mmol, 1 eq) was then added dropwise and the resultingmixture was stirred at 0° C. for 1.5 h. The mixture was diluted withice-water (200 mL) and the organic components were extracted with ethylacetate (3×100 mL). The combined organic layers were washed with brine(150 mL), dried over anhydrous sodium sulfate, filtered and concentratedunder reduced pressure to provide crude compound. The crude material waspurified by silica gel (100-200 mesh) column chromatography using 20%ethyl acetate/hexanes to obtain the title compound (8 g, 81%) as a brownsolid. ¹H NMR (400 MHz, DMSO-d₆) δ 9.50 (s, 1H), 7.85 (d, 1H, J=4 Hz),7.46 (d, 1H, J=7 Hz), 6.50 (dd, 1H, J=5, 8 Hz), 5.22 (s, 1H), 1.89-1.76(m, 1H), 1.42 (s, 9H), 0.85-0.75 (m, 4H). LCMS: m/z=234.2 [M+H], RT=3.09minutes; (Program P1, Column Y).

Step 4: tert-Butyl-[3-(5-cyclopropyl-tetrazol-1-yl)-pyridin-2-yl]-amine

To a stirred solution of compound IV (8.0 g, 34.3 mmol, 1 eq) inacetonitrile (240 mL) was added sodium azide (44 g, 686 mmol, 20 eq) at0° C. Silicon tetrachloride (12 mL, 103 mmol, 3 eq) was added to themixture at 0° C. After the completion of the addition, the mixture wasstirred at 90° C. for 9 h. The mixture was poured into ice cold waterand solid NaHCO₃ was added in portions to adjust the pH to 8. Theresulting mixture was then filtered through a Celite® plug and thefiltrate was collected. The organic components were extracted with ethylacetate (500 mL) and washed with brine (300 mL). The organic layer wasdried over anhydrous sodium sulfate and concentrated in vacuo to providecrude compound. The crude material was purified by silica gel (100-200mesh) column chromatography using 10% ethyl acetate/hexanes to obtaincrude title compound (8 g) as brown sticky solid. LCMS: m/z=259.2 [M+H],RT=3.52 minutes; (Program P1, Column Y).

Step 5:[5-Bromo-3-(5-cyclopropyl-tetrazol-1-yl)-pyridin-2-yl]-tert-butyl-amine

To a stirred solution of compound V (8 g, 31 mmol, 1 eq) in THF (300 mL)was added N-bromosuccinimide (5 g, 27.9 mmol, 0.9 eq) in small portionsat 0° C. After completion of the addition, the mixture was stirred at23° C. for 2 h. The mixture was then concentrated in vacuo and theresidue was diluted with aqueous sodium bicarbonate solution (200 mL) toadjust the pH to 8. The organic components were extracted with ethylacetate (2×200 mL), washed with brine (150 mL), dried over anhydroussodium sulfate and concentrated under reduced pressure to obtain crudecompound. The crude material was purified by silica gel (100-200 mesh)column chromatography using 10% ethyl acetate/hexanes to obtain compound(5.8 g, 50%) as an off-white solid. ¹H NMR (400 MHz, DMSO-d₆) δ 8.36 (d,1H, J=2 Hz), 7.90 (d, 1H, J=2 Hz), 5.89 (s, 1H), 1.82-1.76 (m, 1H), 1.37(s, 9H), 1.14-1.06 (m, 4H). LCMS: m/z=337.5 [M+], RT=3.72 minutes;(Program P1, Column V).

Step 6: 5-Bromo-3-(5-cyclopropyl-tetrazol-1-yl)-pyridin-2-yl-amine

To a solution of compound VI (5.8 g, 17.2 mmol, 1 eq) in methanol (150mL) was added 6 N HCl dropwise (150 mL), with stirring at 0° C. Afterthe addition, the mixture was heated at reflux for 2 h. The mixture wasconcentrated in vacuo and the residue was diluted with saturated aqueoussodium bicarbonate solution to adjust the pH to 8. The organiccomponents were extracted with 10% MeOH/CH₂Cl₂ (3×200 mL). The combinedorganic layers were washed with brine (200 mL), dried over anhydroussodium sulfate and concentrated under reduced pressure to obtain thetitle compound (4.6 g, 95%) as an off-white solid. ¹H NMR (400 MHz,DMSO-d₆) δ 8.28 (d, 1H, J=2 Hz), 7.98 (d, 1H, J=2 Hz), 6.58 (s, 2H),1.84-1.77 (m, 1H), 1.11-1.06 (m, 4H). LCMS: m/z=281.0 [M+], 283.2 [M+2],RT=2.69 minutes; (Program P1, Column V).

Step 7: 6-Amino-5-(5-cyclopropyl-tetrazol-1-yl)-nicotinic acid methylester

To a solution of compound VII (4.6 g, 16.4 mmol, 1 eq) in methanol (140mL) was added DIPEA (18.6 mL, 106.4 mmol, 6.5 eq) and the resultingmixture was degassed under argon in a Parr autoclave vessel. After 10min, PdCl₂(dppf).CH₂Cl₂ (1.6 g, 2 mmol, 0.12 eq) was added to themixture and degassing with argon was continued for another 10 min. Themixture was stirred at 90° C. under 50 psi pressure of CO gas in a Parrautoclave for 16 h. The mixture was filtered through a Celite® pad andthe filtrate was concentrated in vacuo to obtain crude product. Thecrude material was purified by silica gel (100-200 mesh) columnchromatography using 5% MeOH/CH₂Cl₂ to obtain the title compound (3.8 g,89%) as an off-white solid. ¹H NMR (400 MHz, DMSO-d₆) δ 8.72 (d, 1H, J=2Hz), 8.08 (d, 1H, J=2 Hz), 7.24 (brs, 2H), 3.80 (s, 3H), 1.83-1.75 (m,1H), 1.08-1.06 (m, 4H). LCMS: m/z=261.4 [M+H], RT=2.44 minutes; (ProgramR1, Column Y).

Step 8:8-(5-Cyclopropyl-tetrazol-1-yl)-imidazo[1,2-a]pyridine-6-carboxylic acidmethyl ester

To a stirred solution of compound VIII (3.8 g, 14.6 mmol, 1 eq) inethanol (140 mL) were added sodium bicarbonate (12.4 g, 146 mmol, 10eq), a 55% aqueous solution of chloroacetaldehyde (38 mL, 584 mmol, 40eq) and the resulting mixture was heated at reflux for 16 h. The mixturewas filtered through a Celite® pad and the filtrate was concentratedunder reduced pressure. The residue was diluted with ice-cold water (100mL) and the organic components were extracted with ethyl acetate (2×100mL) and 5% MeOH/CH₂Cl₂ (50 mL). The combined organic layers were washedwith brine (150 mL), dried over anhydrous sodium sulfate andconcentrated in vacuo. The crude material was purified by silica gel(100-200 mesh) column chromatography using 10% MeOH/CH₂Cl₂ to obtain thetitle compound as brown sticky solid (7 g, impure), which was carriedforward for the next step. LCMS: m/z=285.2 [M+H], RT=2.42 minutes;(Program P1, Column W)

Step 9:3-Bromo-8-(5-cyclopropyl-tetrazol-1-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester

To a stirred solution of compound IX (7 g impure) in THF (300 mL) wasadded N-bromosuccinimide (3.1 g, 17.3 mmol, 0.7 eq) portionwise at 0° C.After completion of the addition, the mixture was stirred at 23° C. for1.5 h. The mixture was concentrated under reduced pressure and dilutedwith aqueous sodium bicarbonate adjusting the pH to 8. The organiccomponents were extracted with ethyl acetate (2×150 mL) and the combinedorganic layers were washed with brine (150 mL), dried over anhydroussodium sulfate and concentrated in vacuo to obtain crude compound. Thecrude material was purified by silica gel (100-200 mesh) columnchromatography using 20% EtOAc/hexanes to obtain the title compound (4g, 75%) as brownish sticky solid. ¹H NMR (400 MHz, DMSO-d₆) δ 8.98 (d,1H, J=1 Hz), 8.24 (d, 1H, J=1 Hz), 7.98 (s, 1H), 3.96 (s, 3H), 1.99-1.94(m, 1H), 1.10-1.04 (m, 4H). LCMS: m/z=363.1 [M+], 365.0 [M+2], RT=3.33minutes; (Program R1, Column Y).

Step 10:3-Bromo-8-(5-cyclopropyl-tetrazol-1-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid

To a solution of compound X (4 g, 11 mmol, 1 eq) in THF (200 mL) wasadded an aqueous solution of LiOH.H₂O (1.4 g, 33 mmol, 3 eq) dropwise,followed by an addition of methanol (6 mL) and the mixture was stirredat 23° C. for 2 h. The solvents were removed in vacuo and the solidresidue was diluted with water (100 mL). The aqueous layer was washedwith EtOAc (50 mL) and a saturated aqueous solution of citric acid wasadded to the aqueous phase adjusting the pH to 1. The organic componentwas then extracted from the aqueous layer with 10% MeOH/CH₂Cl₂ (100 mL),dried over anhydrous sodium sulfate, filtered and concentrated underreduced pressure to obtain the title compound (3.5 g, 91%) as a deepbrown solid. ¹H NMR (400 MHz, DMSO-d₆) δ 13.87 (brs, 1H), 8.96 (d, 1H,J=1 Hz), 8.18 (d, 1H, J=1 Hz), 7.97 (s, 1H), 1.99-1.96 (m, 1H),1.10-1.04 (m, 4H). LCMS: m/z=349.0 [M+], 351.0 [M+2], RT=2.77 minutes;(Program R1, Column Y).

Step 11:3-Bromo-8-(5-cyclopropyl-tetrazol-1-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid (6-methyl-pyridin-3-ylmethyl)-amide

To a solution of compound XI (1 g, 2.86 mmol, 1 eq) in DMF (100 mL) wereadded HATU (1.41 g, 3.72 mmol, 1.3 eq) and DIPEA (4 mL) at 0° C. underargon. After 10 min, a DMF solution ofC-(6-methyl-pyridin-3-yl)-methylamine (524 mg, 4.3 mmol, 1.5 eq) wasadded to the mixture and the resulting mixture was stirred at 23° C. for16 h. The mixture was diluted with ice cold water (50 mL) and theorganic components were extracted with ethyl acetate (2×50 mL) and 10%MeOH/CH₂Cl₂ (50 mL). The combined organic layers were washed with brine(100 mL), dried over anhydrous sodium sulfate, filtered and concentratedunder reduced pressure to obtain crude compound. The crude product waspurified by flash Combiflash™ chromatography using 100-200 mesh silicagel eluting with 9% MeOH/CH₂Cl₂ to obtain the title compound (660 mg,52%) as an orange solid. ¹H NMR (400 MHz, DMSO-d₆) δ 9.48 (t, 1H, J=5Hz), 9.13 (s, 1H), 8.47 (s, 1H), 8.25 (s, 1H), 7.94 (s, 1H), 7.67 (d,1H, J=8 Hz), 7.23 (d, 1H, J=8 Hz), 4.53 (d, 2H, J=5 Hz), 2.44 (s, 3H),2.02-1.93 (m, 1H), 1.11-1.01 (m, 4H). LCMS: m/z=453.2 [M+], 455.0 [M+2],RT=2.13 minutes; (Program R1, Column Y)

Step 12:8-(5-Cyclopropyl-1H-tetrazol-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide

To a DMF (30 mL) solution of compound XII (650 mg, 1.44 mmol, 1 eq)degassed with argon in a reaction tube was added compound VIa (832 mg,2.2 mmol, 1.5 eq) and the resulting mixture was degassed with argon for10 min, before the addition of Pd(PPh₃)₄ (162 mg, 0.14 mmol, 0.1 eq).Degassing with argon was done for another 15 min, the reaction tube wassealed, then heated at 120° C. for 4 h. The mixture was filtered througha Celite® pad and the filtrate was concentrated under reduced pressureto provide a solid residue. The organic components were then extractedwith EtOAc (2×100 mL) and 10% MeOH/CH₂Cl₂ (100 mL), and the combinedorganic layers were washed with brine (100 mL), dried over anhydroussodium sulfate, filtered and concentrated to provide crude compound. Thecrude product was purified by flash Combiflash™ chromatography using100-200 mesh silica gel eluting with 4% MeOH/CH₂Cl₂ to obtain the titlecompound (400 mg, 59%) as an off-white solid. ¹H NMR (400 MHz, DMSO-d₆)δ 9.39 (m, 1H), 9.22 (s, 1H), 8.44 (s, 1H), 8.21 (s, 1H), 7.91 (s, 1H),7.64 (d, 1H, J=8 Hz), 7.46 (d, 1H, J=3 Hz), 7.21 (d, 1H, J=8 Hz), 7.05(d, 1H, J=3 Hz), 4.50 (d, 2H, J=6 Hz), 2.56 (s, 3H), 2.44 (s, 3H),2.06-1.96 (m, 1H), 1.11-1.06 (m, 4H). LCMS: m/z=471.0 [M+H]⁺, RT=6.07minutes; (Program R1, Column Y).

Example 178-(5-(Hydroxymethyl)-1H-tetrazol-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide

Compound III was prepared as discussed in scheme 32.

Step 1: Acetic acid (2-tert-butylamino-pyridin-3-ylcarbamoyl)-methylester

To a solution of compound III (3 g, 18.2 mmol, 1 eq) in CH₂Cl₂ (100 mL)was added DIPEA (9.52 mL, 54.5 mmol, 3 eq) dropwise at 0° C. and theresulting mixture was stirred for 10 min. To the mixture was then addeda solution of acetoxy acetylchloride (1.95 mL, 18.2 mmol, 1 eq) inCH₂Cl₂ (5 mL) dropwise and continued stirring at 0° C. for 3 h. Themixture was diluted with ice-cold water (50 mL) and the organiccomponents were extracted with CH₂Cl₂ (2×70 mL). The combined organiclayers were washed with brine (100 mL), dried over anhydrous sodiumsulfate and concentrated under reduced pressure to get crude compound.The crude material was purified by silica gel (100-200 mesh) columnchromatography with 30% ethyl acetate/hexanes to obtain the titlecompound (3 g, 60%) as brownish solid. ¹H NMR (400 MHz, DMSO-d₆) δ 9.39(s, 1H), 7.90 (d, 1H, J=5 Hz), 7.36 (d, 1H, J=7 Hz), 6.52 (dd, 1H, J=5,7 Hz), 5.10 (s, 1H), 4.66 (s, 2H), 2.12 (s, 3H), 1.41 (s, 9H). LCMS:m/z=266.0 [M+H], RT=1.20 minutes; (Program R1, Column Y).

Step 2: Acetic acid1-(2-tert-butylamino-pyridin-3-yl)-1H-tetrazol-5-ylmethyl ester

To a stirred solution of compound IV (3 g, 11.3 mmol, 1 eq) inacetonitrile (100 mL) were added sodium azide (7.35 g, 113 mmol, 10 eq)and silicon tetrachloride (3.9 mL, 33.9 mmol, 3 eq) at 0° C. and theresulting mixture was stirred at 90° C. for 16 h. The mixture was pouredinto ice cold water and solid NaHCO₃ was added in portions to adjust thepH to 8. The resulting mixture was the filtered through a Celite® padand the filtrate was collected. The organic components were extractedwith ethyl acetate (200 mL) and washed with brine (100 mL). The organiclayer was dried over anhydrous sodium sulfate, filtered and concentratedin vacuo to provide crude title compound (4 g) as an off-white stickysolid. ¹H NMR (400 MHz, DMSO-d₆) δ 8.27 (dd, 1H, J=2, 5 Hz), 7.54 (dd,1H, J=2, 8 Hz), 6.71 (dd, 1H, J=5, 8 Hz), 5.56 (s, 1H), 5.28 (s, 2H),1.91 (s, 3H), 1.38 (s, 9H). LCMS: m/z=291.1 [M+H], RT=3.82 minutes;(Program R1, Column Y).

Step 3: Acetic acid1-(5-bromo-2-tert-butylamino-pyridin-3-yl)-1H-tetrazol-5-ylmethyl ester

To a solution of compound V (4 g, 13.8 mmol, 1 eq) in THF (100 mL) wasadded N-bromosuccinimide (2.2 g, 12.4 mmol, 0.9 eq) in small portionswith stirring at 0° C. After completion of the addition, the mixture wasstirred at 23° C. for 2 h. The mixture was concentrated in vacuo and theresidue was diluted with aqueous sodium bicarbonate to adjust the pH to8. The organic components were extracted with ethyl acetate (2×100 mL),the combined extracts were washed with brine (100 mL), dried overanhydrous sodium sulfate, filtered and concentrated under reducedpressure to obtain crude compound. The crude material was purified bysilica gel (100-200 mesh) column chromatography using 20% ethylacetate/hexanes to obtain the title compound (3.0 g, 72%, two steps) asa brown solid. ¹H NMR (400 MHz, DMSO-d₆) δ 8.37 (d, 1H, J=2 Hz), 7.89(d, 1H, J=2 Hz), 5.88 (s, 1H), 5.30 (s, 2H), 1.93 (s, 3H), 1.36 (s, 9H).LCMS: m/z=371.0 [M+2], RT=4.11 minutes; (Program R1, Column Y).

Step 4: Acetic acid1-(2-amino-5-bromo-pyridin-3-yl)-1H-tetrazol-5-ylmethyl ester

To a stirred solution of compound VI (3 g, 8.13 mmol, 1 eq) in CH₂Cl₂(100 mL) was added trifluoroacetic acid (100 mL) dropwise at 23° C. andthe resulting mixture was stirred at 23° C. for 16 h. The mixture wascooled to 0° C. and diluted with saturated aqueous sodium bicarbonatesolution to adjust the pH to 8. The organic components were extractedwith CH₂Cl₂ (2×70 mL) and the combined extracts were washed with brine(75 mL). The organic layer was dried over anhydrous sodium sulfate,filtered and concentrated under reduced pressure to obtain the titlecompound (1.7 g, 68%) as an off-white solid. ¹H NMR (400 MHz, DMSO-d₆) δ8.29 (d, 1H, J=2 Hz), 7.94 (d, 1H, J=2 Hz), 6.60 (s, 2H), 5.32 (s, 2H),1.93 (s, 3H). LCMS: m/z=313.0 [M+], 315.2 [M+2], RT=3.09 minutes;(Program R1, Column Y).

Step 5: Acetic acid1-(6-bromo-imidazo[1,2-a]pyridin-8-yl)-1H-tetrazol-5-ylmethyl ester

To a stirred solution of compound VII (1.7 g, 5.4 mmol, 1 eq) in ethanol(100 mL) were added sodium bicarbonate (4.6 g, 54 mmol, 10 eq) and a 55%aqueous solution of chloroacetaldehyde (26 mL, 216 mmol, 40 eq), and theresulting mixture was heated at reflux for 16 h. The mixture wasfiltered through a Celite® pad and the filtrate was concentrated underreduced pressure. The filtrate was diluted with ice-cold water (100 mL)and the organic components were extracted with ethyl acetate (2×70 mL)and 5% MeOH/CH₂Cl₂ (75 mL). The combined organic layers were washed withbrine (100 mL), dried over anhydrous sodium sulfate and concentrated invacuo. The crude material was purified by silica gel (100-200 mesh)column chromatography using 10% MeOH/CH₂Cl₂ to obtain the title compoundas a brown sticky solid (1.4 g, 75%), which was carried forward for thenext step. ¹H NMR (400 MHz, DMSO-d₆) δ 9.24 (d, 1H, J=1 Hz), 8.16 (s,1H), 8.02 (d, 1H, J=2 Hz), 7.70 (s, 1H), 5.45 (s, 2H), 1.84 (s, 3H).LCMS: m/z=337.0 [M+], 339.0 [M+2], RT=2.94 minutes; (Program R1, ColumnY)

Step 6:8-(5-Hydroxymethyl-tetrazol-1-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester

To a solution of compound VIII (1.4 g, 4.15 mmol, 1 eq) in MeOH (100 mL)was added DIPEA (5 mL, 27 mmol, 6.5 eq) and the resulting mixture wasdegassed with argon for 10 min. To the mixture was then addedPdCl₂(dppf) and CH₂Cl₂ (408 mg, 0.5 mmol, 0.12 eq) and the resultingmixture was degassed with argon for another 10 min. The mixture was thenstirred at 90° C. under CO atmosphere with a pressure of 50 psi in aParr autoclave for 16 h. The mixture was filtered through a Celite® padand the filtrate was concentrated in vacuo to obtain crude product. Thecrude material was purified by silica gel (100-200 mesh) columnchromatography using 5% MeOH/CH₂Cl₂ to obtain the title compound (0.8 g,71%) as an off-white solid. ¹H NMR (400 MHz, DMSO-d₆) δ 9.62 (s, 1H),8.34 (s, 1H), 8.04 (s, 1H), 7.94-7.85 (m, 1H), 7.77 (s, 1H), 4.82 (d,2H, J=6 Hz), 3.93 (s, 3H). LCMS: m/z=275.4 [M+H], RT=2.44 minutes;(Program R1, Column Y).

Step 7:8-(5-Acetoxymethyl-tetrazol-1-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester

To a stirred solution of compound IX (0.8 g, 2.92 mmol, 1 eq) in CH₂Cl₂(50 mL) was added TEA (0.82 mL, 5.84 mmol, 2 eq) dropwise at 0° C., andthe resulting mixture was stirred for 15 min Acetyl chloride (0.42 mL,5.84 mmol, 2 eq) was added to the mixture and the resulting mixture wasstirred at 23° C. for 2 h. The mixture was concentrated under reducedpressure and diluted with water (30 mL). The organic components wereextracted with ethyl acetate (2×20 mL) and the combined extracts werewashed with brine (30 mL). The organic layer was dried over anhydroussodium sulfate, filtered and concentrated under reduced pressure toobtain the title compound (1.2 g) crude as an off-white solid. LCMS:m/z=317.2 [M+H], RT=2.76 minutes; (Program R1, Column Y)

Step 8:8-(5-Acetoxymethyl-tetrazol-1-yl)-3-(5-methyl-thiophen-2-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester

To a stirred solution of compound X (1.2 g, 3.8 mmol, 1 eq) in THF (100mL) was added N-bromosuccinimide (0.61 g, 3.4 mmol, 0.9 eq) at 0° C. inportions and the resulting mixture was stirred at 23° C. for 1.5 h. Themixture was concentrated under reduced pressure and diluted with aqueoussodium bicarbonate adjusting the pH to 8. The organic components wereextracted with ethyl acetate (2×50 mL) and the combined extracts werewashed with brine (70 mL), dried over anhydrous sodium sulfate, filteredand concentrated in vacuo to obtain crude compound. The crude materialwas purified by silica gel (100-200 mesh) column chromatography using20% EtOAc/hexanes to obtain the title compound (0.8 g, 69%) as greenishyellow solid. ¹H NMR (400 MHz, DMSO-d₆) δ 9.00 (s, 1H), 8.26 (s, 1H),7.99 (s, 1H), 5.41 (s, 2H), 3.97 (s, 3H), 1.87 (s, 3H). LCMS: m/z=395.1[M+], 397.0 [M+2], RT=3.31 minutes; (Program R1, Column Y).

Step 9:8-(5-Acetoxymethyl-tetrazol-1-yl)-3-bromo-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester

To a DMF (50 mL) solution of compound XI (0.8 g, 2.02 mmol, 1 eq),degassed with argon, in a reaction tube was added compound VIa (1.17 g,3.03 mmol, 1.5 eq) and the resulting mixture was degassed with argon for10 min. To the mixture was added Pd(PPh₃)₄ (0.23 g, 0.2 mmol, 0.1 eq)and the resulting mixture was degassed with argon for another 15 min.The reaction tube was then sealed and heated at 120° C. for 4 h. Themixture was filtered through a Celite® pad and the filtrate wasconcentrated under reduced pressure to provide a solid residue. Theorganic components were then extracted with EtOAc (2×50 mL) and 10%MeOH/CH₂Cl₂ (50 mL), and the combined extracts were washed with brine(100 mL). The organic layer was dried over anhydrous sodium sulfate,filtered and concentrated to provide crude compound. The crude productwas purified by flash Combiflash™ chromatography using 100-200 meshsilica gel eluting with 4% MeOH/CH₂Cl₂ to obtain the title compound(0.64 g, 75%) as an off-white solid. ¹H NMR (400 MHz, DMSO-d₆) δ 9.17(d, 1H, J=1 Hz), 8.20 (s, 1H), 7.97 (s, 1H), 4.45 (d, 1H, J=4 Hz), 7.06(d, 1H, J=3 Hz), 5.44 (s, 2H), 3.94 (s, 3H), 2.57 (s, 3H), 1.89 (s, 3H).LCMS: m/z=413.0 [M+H], RT=3.73 minutes; (Program R1, Column Y).

Step 10:8-(5-Hydroxymethyl-tetrazol-1-yl)-3-(5-methyl-thiophen-2-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid

To a solution of compound XII (0.64 g, 1.55 mmol, 1 eq) in THF (50 mL)was added an aqueous solution of LiOH.H₂O (0.2 g, 4.66 mmol, 3 eq)dropwise followed by addition of methanol (3 mL) and the resultingmixture was stirred at 23° C. for 2 h. The solvent of the mixture wasremoved in vacuo and the solid residue was diluted with water (40 mL).The aqueous layer was washed with the EtOAc (30 mL) and a saturatedaqueous solution of citric acid was added to the aqueous part adjustingthe pH to 1. The organic component was then extracted from the aqueouslayer with 10% MeOH/CH₂Cl₂ (100 mL), dried over anhydrous sodiumsulfate, filtered and concentrated under reduced pressure to obtain thetitle compound (0.35 g, 63%) as brownish solid. ¹H NMR (400 MHz,DMSO-d₆) δ 12.30 (brs, 1H), 9.15 (s, 1H), 8.08 (s, 1H), 7.95 (s, 1H),7.44 (d, 1H, J=3 Hz), 7.05 (s, 1H), 5.79-5.69 (m, 1H), 4.85 (d, 2H, J=5Hz), 2.57 (s, 3H). LCMS: m/z=357.2 [M+H], RT=3.04 minutes; (Program R1,Column W)

Step 11:845-(Hydroxymethyl)-1H-tetrazol-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide

To a solution of compound XIII (0.35 g, 0.98 mmol, 1 eq) in DMF (30 mL)were added HATU (0.48 g, 1.27 mmol, 1.3 eq) and DIPEA (2 mL) at 0° C.under an argon atmosphere. After 10 minutes, a DMF solution ofC-(6-methyl-pyridin-3-yl)-methylamine (0.18 g, 1.47 mmol, 1.5 eq) wasadded and the resulting mixture was stirred at 23° C. for 16 h. Themixture was diluted with ice cold water (30 mL) and the organiccomponents were extracted with ethyl acetate (2×50 mL) and 10%MeOH/CH₂Cl₂ (50 mL). The combined organic layers were washed with brine(80 mL), dried over anhydrous sodium sulfate, filtered and concentratedunder reduced pressure to obtain crude compound. The crude product waspurified by flash Combiflash™ chromatography using 100-200 mesh silicagel eluting with 9% MeOH/CH₂Cl₂ to obtain the title compound (0.25 g,55%) as an off-white solid. ¹H NMR (400 MHz, DMSO-d₆) δ 9.46-9.38 (m,1H), 9.21 (s, 1H), 8.45 (s, 1H), 8.18 (s, 1H), 7.90 (s, 1H), 7.68-7.63(m, 1H), 7.46 (d, 1H, J=3 Hz), 7.26-7.20 (m, 1H), 7.05 (d, 1H, J=3 Hz),5.80-5.70 (m, 1H), 4.87 (d, 2H, J=5 Hz), 4.50 (d, 2H, J=5 Hz), 2.56 (s,3H), 2.44 (s, 3H). LCMS: m/z=461.2 [M+H]⁺, RT=2.30 minutes; (Program R1,Column W).

Example 188-(5-(Difluoromethyl)-1H-tetrazol-yl)-N-((6-methylpyridin-3-yl)methyl)-3(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide

Step 1: 6-Bromo-imidazo[1,2-a]pyridin-8-ylamine

To a solution of compound I (10 g, 53 mmol, 1 eq) in ethanol (200 mL)were added sodium bicarbonate (8.92 g, 106 mmol, 2 eq) andchloroacetaldehyde (8.6 mL, 133 mmol, 2.5 eq) and the resulting mixturewas stirred at 120° C. for 16 h. The mixture was filtered and thefiltrate was concentrated in vacuo to obtain a solid residue. Theresidue was then washed with water (200 mL) and organic components wereextracted with ethyl acetate (800 mL), dried over anhydrous sodiumsulfate, filtered and the solvent was removed under reduced pressure toprovide crude compound. The crude product was purified by flashCombiflash™ chromatography using 100-200 mesh silica gel eluting with 2%MeOH/CH₂Cl₂ to obtain the title compound (6 g, 53%) as a brown solid. ¹HNMR (400 MHz, DMSO-d₆) δ 8.05 (d, 1H, J=2 Hz), 7.77 (d, 1H, J=1 Hz),7.41 (d, 1H, J=1 Hz), 6.30 (d, 1H, J=2 Hz), 5.98 (s, 2H). LCMS:m/z=213.6 [M+2], RT=0.79 minutes; (Program R1, Column Y).

Step 2: 8-Amino-imidazo[1,2-a]pyridine-6-carboxylic acid methyl ester

To a solution of compound II (6 g, 28 mmol, 1 eq) in MeOH (100 mL) wasadded DIPEA (26 mL, 140 mmol, 5 eq) and the resulting mixture wasdegassed with argon for 10 min, then PdCl₂(dppf).CH₂Cl₂ (2.3 g, 2.8 mol,0.1 eq) was added. Degassing with argon was repeated for 10 min and thereaction vessel was attached to Parr autoclave stirring at 90° C. at 50psi under CO atmosphere for 16 h. The mixture was filtered through aCelite® pad and the filtrate was concentrated in vacuo to obtain a solidresidue. The residue was then washed with water (100 mL) and the organiccomponents were extracted with ethyl acetate (800 mL), dried overanhydrous sodium sulfate and the solvent was removed under reducedpressure to provide crude compound. The crude product was purified byflash Combiflash™ chromatography using 100-200 mesh silica gel elutingwith 40% EtOAc/hexanes to obtain the title compound (3.5 g, 65%) as anoff-white solid. ¹H NMR (400 MHz, DMSO-d₆) δ 8.57 (d, 1H, J=1 Hz), 7.97(s, 1H), 7.51 (s, 1H), 6.67 (d, 1H), 5.87 (s, 2H), 3.84 (s, 3H). LCMS:m/z=191.8 [M+H], RT=0.78 minutes; (Program R1, Column Y).

Step 3: 8-(2,2-Difluoro-acetylamino)-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester

To a solution of compound III (4 g, 20 mmol, 1 eq), difluoroacetic acid(17.16 mL, 272 mmol, 13 eq) and TEA (8.82 mL, 62.8 mmol, 3 eq) in DMF(100 mL) was added T3P (16 mL, 26.8 mmol, 1.3 eq) dropwise undernitrogen atmosphere and the mixture was stirred at reflux for 5 h. Themixture was then diluted with water (100 mL) and the organic componentswere extracted with ethyl acetate (800 mL). The organic layer was washedwith brine (300 mL), dried over anhydrous sodium sulfate, filtered andsolvent was removed under reduced pressure to provide crude compound.The crude product was purified by flash Combiflash™ chromatography using100-200 mesh silica gel eluting with 35% EtOAc/hexanes to obtain thetitle compound (3 g, 53%) as a grey solid. ¹H NMR (400 MHz, DMSO-d₆) δ11.09 (s, 1H), 9.19 (d, 1H, J=1 Hz), 8.40 (d, 1H, J=1 Hz), 8.18 (d, 1H,J=1 Hz), 7.72 (d, 1H, J=1 Hz), 6.79-6.16 (m, 1H), 3.90 (s, 3H). LCMS:m/z=269.7 [M+H], RT=2.40 minutes; (Program R1, Column W).

Step 4:8-(5-Difluoromethyl-tetrazol-1-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester

Route 1

To a solution of compound IV (3 g, 11.15 mmol, 1 eq) in acetonitrile(100 mL) was added sodium azide (29 g, 446.1 mmol, 40 eq) and theresulting mixture was cooled to 0° C. Silicon tetrachloride (13 mL,111.5 mmol, 10 eq) was added and the resulting mixture was stirred at90° C. for 9 h. The mixture was poured into ice cold water and solidNaHCO₃ was added in portions to adjust the pH to 8. The resultingmixture was then filtered through a Celite® pad and filtrate wascollected. The organic components were then extracted with ethyl acetate(400 mL) after washing with water (100 mL). The organic layer was thendried over anhydrous sodium sulfate, filtered and the solvent wasremoved under reduced pressure to provide crude compound. The crudeproduct was purified by flash Combiflash™ chromatography using 100-200mesh silica gel eluting with 40% EtOAc/hexanes to obtain the titlecompound (1 g, 30%) as a brownish sticky solid. ¹H NMR (400 MHz,DMSO-d₆) δ 9.66 (d, 1H, J=1 Hz), 8.36 (s, 1H), 8.26 (d, 1H, J=1 Hz),7.77 (d, 1H, J=1 Hz), 7.60 (t, 1H, J=51 Hz), 3.94 (s, 3H). LCMS:m/z=295.1 [M+H], RT=3.11 minutes; (Program R1, Column Y).

Route 2

8-(2,2-Difluoro-thioacetylamino)-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester V

To a solution of compound IV (26.5 g, 98.5 mmol, 1 eq) in 1,4-dioxane(1.4 L) were added hexamethyldisiloxane (84.19 mL, 394 mmol, 4 eq) andphosphorus pentasulfide (21.89 g, 98.5 mmol, 1 eq) and the mixturerefluxed under stirring for 6-8 h. The mixture was cooled to roomtemperature, quenched with saturated aqueous sodium bicarbonate solutionto adjust the pH to 8. The organic components were then extracted withethyl acetate (2 L), after washing with water (1 L). The organic layerwas then dried over anhydrous sodium sulfate and solvent was removedunder reduced pressure to get crude compound. The crude was washed withethanol to afford compound V (21 g, 75%) as brown solid. ¹H NMR (400MHz, DMSO-d₆) δ 9.31 (s, 1H), 8.57 (s, 1H), 8.21 (s, 1H), 7.73 (t, J=95Hz, 1H), 6.67 (m, 1H), 5.87 (m, 1H), 3.90 (s, 3H); LCMS: m/z=286.0[M+H], RT=2.58 minutes; (Program P1, Column Y).

8-(5-Difluoromethyl-tetrazol-1-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester VI

To a solution of compound V (21 g, 73.6 mmol, 1 eq) in THF (300 mL) at0° C., were added mercury (II) acetate (46.96 g, 147 mmol, 2 eq) andtrimethylsilylazide (24.3 mL, 184 mmol, 2.5 eq) and the mixture wasstirred at 0° C. for 1 h. The mixture was quenched with saturatedaqueous ammonium chloride solution, filtered and the filtrate wascollected. The organic components of the filtrate were then extractedwith ethyl acetate (1 L) after washing with water (1 L). The organiclayer was then dried over anhydrous sodium sulfate and solvent wasremoved under reduced pressure to get crude compound. The crude compoundwas washed with ethanol to afford compound V (21 g, 97%) as off whitesolid. ¹H NMR (400 MHz, DMSO-d₆) δ 9.66 (s, 1H), 8.35 (s, 1H), 8.26 (s,1H), 7.77 (s, 1H), 7.60 (t, J=52 Hz, 1H), 3.93 (s, 3H); LCMS: m/z=295.1[M+H], RT=2.77 minutes; (Program P1, Column V).

Step 5: 3-Bromo-8-(5-difluoromethyl-tetrazol-1yl)-imidazo[1,2-a]pyridine-6-carboxylic acid methyl ester

To a solution of compound V (1 g, 3.4 mmol, 1 eq) in THF (100 mL) wasadded N-bromosuccinamide (0.6 g, 3.4 mmol, 1 eq) and the resultingmixture was stirred at 23° C. for 3 h. The volatiles of the mixture wereremoved under reduced pressure and the residue was diluted with aqueoussodium bicarbonate to adjust the pH to 8. The organic components wereextracted with ethyl acetate (150 mL) after washing with water (50 mL).The organic layer was dried over anhydrous sodium sulfate, filtered andthe solvent was removed under reduced pressure to provide the crudecompound. The crude product was purified by flash Combiflash™chromatography using 100-200 mesh silica gel eluting with 30%EtOAc/hexanes to obtain the title compound (0.8 g, 63%) as a brownsolid. ¹H NMR (400 MHz, DMSO-d₆) δ 9.01 (d, 1H, J=1 Hz), 8.40 (d, 1H,J=1 Hz), 7.99 (s, 1H), 7.56 (t, 1H, J=51 Hz), 3.97 (s, 3H). LCMS:m/z=372.9 [M+], 375.0 [M+2], RT=3.52 minutes; (Program R1, Column Y).

Step 6:3-Bromo-8-(5-difluoromethyl-tetrazol-1-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester

To a solution of compound VI (0.8 g, 2.14 mmol, 1 eq) in THF (50 mL) andMeOH (4 mL) was added an aqueous solution of LiOH, H₂O (0.27 g, 6.42mmol, 3 eq) and the resulting mixture was stirred at 23° C. for 1 h. Thesolvent of the mixture was removed in vacuo and the solid residue wasdiluted with water (50 mL). The residue was washed with EtOAc (30 mL)and the aqueous layer was acidified with citric acid adjusting the pHto 1. The organic components were then extracted with 10% MeOH/CH₂Cl₂(100 mL), dried over anhydrous sodium sulfate, filtered and concentratedunder reduced pressure to provide the title compound (0.5 g, 66%) as abrown solid. ¹H NMR (400 MHz, DMSO-d₆) δ 9.95 (s, 1H), 8.98 (d, 1H, J=1Hz), 8.35 (d, 1H, J=1 Hz), 7.97 (s, 1H), 7.56 (t, 1H, J=47 Hz). LCMS:m/z=359.0 [M+], 361.1 [M+2], RT=3.03 minutes; (Program R1, Column Y).

Step 7:3-Bromo-8-(5-difluoromethyl-tetrazol-1-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid (6-methyl-pyridin-3-ylmethyl)-amide

To a solution of compound VII (0.5 g, 1.39 mmol, 1 eq) in DMF (50 mL)were added HATU (0.7 g, 1.8 mmol, 1.3 eq) and DIPEA (0.74 mL, 4.17 mmol,3 eq) under argon atmosphere at 0° C. A DMF solution ofC-(6-methyl-pyridin-3-yl)-methylamine (0.25 g, 2.09 mmol, 1.5 eq) wasadded and the resulting mixture was stirred at 23° C. for 16 h. Themixture was diluted with ice water (40 mL) and the organic componentswere extracted with EtOAc (2×50 mL) and 10% MeOH/CH₂Cl₂ (50 mL), and thecombined extracts were washed with brine (50 mL). The organic layer wasdried over anhydrous sodium sulfate, filtered and concentrated underreduced pressure to provide the crude compound. The crude product waspurified by flash Combiflash chromatography using 100-200 mesh silicagel eluting with 5% MeOH/CH₂Cl₂ to obtain compound (0.4 g, 62%) as anorange solid. ¹H NMR (400 MHz, DMSO-d₆) δ 9.53 (t, 1H, J=6 Hz), 9.18 (s,1H), 8.47 (s, 1H), 8.37 (s, 1H), 7.94 (s, 1H), 7.70-7.44 (m, 2H), 7.23(d, 1H, J=8 Hz), 4.53 (d, 2H, J=5 Hz), 2.45 (s, 3H). LCMS: m/z=463.0[M+], 465.0 [M+2], RT=1.94 minutes; (Program R1, Column W).

Step 8:845-(Difluoromethyl)-1H-tetrazol-yl)-N-((6-methylpyridin-3-yl)methyl)-3(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide

To a DMF (20 mL) solution of compound VIII (0.4 g, 0.86 mmol, 1 eq),degassed with argon, in a reaction tube was added compound VIa (0.50 g,1.29 mmol, 1.5 eq) and the resulting mixture was degassed with argon for10 min, followed by the addition of Pd(PPh₃)₄ (0.1 g, 0.086 mmol, 0.1eq). Further degassing with argon was done for another 15 min and thereaction tube was sealed then heated at 120° C. for 5 h. The mixture wasfiltered through a Celite® pad and the filtrate was concentrated underreduced pressure to provide a solid residue. The organic components werethen extracted with EtOAc (2×40 mL) and 10% MeOH/CH₂Cl₂ (50 mL) and thecombined extracts were washed with brine (50 mL). The organic layer wasdried over anhydrous sodium sulfate, filtered and concentrated toprovide crude compound. The crude product was purified by flashCombiflash™ chromatography using 100-200 mesh silica gel eluting with 4%MeOH/CH₂Cl₂ to obtain the title compound (0.18 g, 44%) as an off-whitesolid. ¹H NMR (400 MHz, DMSO-d₆) δ 9.45-9.36 (m, 1H), 9.21 (s, 1H), 8.42(s, 1H), 8.30 (s, 1H), 7.88 (s, 1H), 7.73-7.46 (m, 3H), 7.19 (d, 1H, J=8Hz), 7.03 (s, 1H), 4.48 (d, 2H, J=5 Hz), 2.53 (s, 3H), 2.41 (s, 3H).LCMS: m/z=481.0 [M+H]⁺, RT=2.80 minutes; (Program R1, Column W).

Example 19 (R)-8-(5-(Difluoromethyl)-1H-tetrazol-1-yl)-N-(1(3-methyl-1,2,4-oxadiazol-5-yl)ethyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide

Following the experimental procedure described for Example 18, compoundVI was prepared.

Step 6:8-(5-Difluoromethyl-tetrazol-1-yl)-3-(5-methyl-thiophen-2-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester

To a toluene-DMF (10:1, 170 mL) solution of compound VI (1.8 g, 4.82mmol, 1 eq), degassed with argon, was added compound VIa (2.80 g, 7.23mmol, 1.5 eq) and the resulting mixture was degassed with argon for 10minutes before the addition of Pd(PPh₃)₄ (0.55 g, 0.48 mmol, 0.1 eq).Further degassing with argon was done for another 15 min and theresulting mixture was at 120° C. and stirred for 30 min. As the TLCshowed the presence of starting material, heating was continued withconstant TLC monitoring at 15 minute intervals. After 1 h, as thestarting material was found to be consumed completely, the mixture wasallowed to cool to room temperature and filtered through a Celite® pad.The filtrate was concentrated under reduced pressure to provide a solidresidue from which the organic components were extracted with EtOAc(2×100 mL). The combined organic layers were washed with brine (100 mL),dried over anhydrous sodium sulfate and concentrated to provide a crudesolid compound. The crude solid material was washed with 20%EtOAc/hexane (2×50 mL), followed by pentane (2×50 mL) and the residuewas dried in vacuo to obtain pure product. The combined organic washeswere purified by flash Combiflash™ chromatography using 100-200 meshsilica gel eluting with 20% EtOAc/hexanes to obtain pure product whichwas combined with the solid residue to provide the title compound (1.4g, 74%) as a yellow solid. ¹H NMR (400 MHz, DMSO-d₆) δ 9.18 (s, 1H),8.35 (s, 1H), 7.96 (s, 1H), 7.61 (t, 1H, J=51 Hz), 7.46 (d, 1H, J=3 Hz),7.06 (d, 1H, J=3 Hz), 3.94 (s, 3H), 2.57 (s, 3H). LCMS: m/z=391.1 [M+H],RT=3.46 minutes; (Program P1, Column V)

Step 7:8-(5-Difluoromethyl-tetrazol-1-yl)-3-(5-methyl-thiophen-2-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid

To a solution of compound VII (0.6 g, 1.54 mmol, 1 eq) in THF (60 mL)was added saturated aqueous solution of LiOH.H₂O (0.19 g, 4.61 mmol, 3eq) and the resulting mixture was stirred at 10° C. for 10 min. To themixture was then added MeOH (2 mL) to make the mixture a homogeneoussolution and stirring was continued at 23° C. for another 2 h. Thesolvent of the mixture was removed in vacuo and the solid residue wasdiluted with water and washed with EtOAc. The aqueous layer wasacidified with citric acid adjusting the pH to 1 and the organiccomponents were extracted with 20% MeOH/CH₂Cl₂ (2×30 mL). The combinedorganic layers were then washed with brine, dried over anhydrous sodiumsulfate, filtered and concentrated under reduced pressure to provide thetitle compound (0.45 g, 78%) as a brownish solid. ¹H NMR (400 MHz,DMSO-d₆) δ 13.88 (brs, 1H), 9.18 (s, 1H), 8.30 (s, 1H), 7.95 (s, 1H),7.61 (t, 1H, J=51 Hz), 7.45 (d, 1H, J=3 Hz), 7.05 (d, 1H, J=3 Hz), 2.57(s, 3H). LCMS: m/z=376.9 [M+H], RT=2.52 minutes; (Program P1, Column V)

Step 8:(R)-8-(5-(Difluoromethyl)-1H-tetrazol-1-yl)-N-(1-(3-methyl-1,2,4-oxadiazol-5-yl)ethyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide

To a stirred solution of compound VIII (0.15 g, 0.4 mmol, 1 eq) in DMF(10 mL) were added HATU (0.2 g, 0.52 mmol, 1.3 eq) and DIPEA (0.7 mL)under argon atmosphere at 0° C. and after 10 minutes1-(3-methyl-[1,2,4]oxadiazol-5-yl)-ethylamine (0.76 g, 0.6 mmol, 1.5 eq)was added and the resulting mixture was stirred at 23° C. for 16 h. Themixture was diluted with ice water and the organic components wereextracted with EtOAc and 10% MeOH/CH₂Cl₂, then washed with brine. Theorganic layer was dried over anhydrous sodium sulfate, filtered andconcentrated under reduced pressure to give crude compound which waspurified by flash Combiflash™ chromatography using 100-200 mesh silicagel eluting with 5% MeOH/CH₂Cl₂ to obtain the title compound as an offwhite solid. The racemic compound was resolved by purification withchiral HPLC to obtain the pure (R)-enantiomer (0.10 g, 5.2%) as ayellowish solid. ¹H NMR (400 MHz, DMSO-d₆) δ 9.60 (d, 1H, J=7 Hz), 9.25(s, 1H), 8.36 (s, 1H), 7.92 (s, 1H), 7.63 (t, 1H, J=51 Hz), 7.49 (d, 1H,J=3 Hz), 7.07 (m, 1H), 5.46-5.33 (m, 1H), 2.56 (s, 3H), 2.33 (s, 3H),1.62 (d, 3H, J=7 Hz). LCMS: m/z=486.3 [M+H]⁺, RT=3.31 minutes; (ProgramP1, Column V).

Example 20(S)—N-(1-(4H-1,2,4-Triazol-3-yl)ethyl)-8-(N-methylisobutyramido)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide

Following the experimental procedure described for Example 2, compoundIII was prepared.

Step 3: 8-Isobutyrylamino-imidazo[1,2-a]pyridine-6-carboxylic acidmethyl ester

To a solution of compound III (2 g, 10.47 mmol, 1 eq) in dry THF (50 mL)was added pyridine (1.6 mL, 20.94 mmol, 2 eq) and isobutyryl chloride(2.2 mL, 20.94 mmol, 2 eq) and the resulting mixture was stirred at 0°C. under an argon atmosphere for 1 h. The mixture was quenched withwater (100 mL) and the organic components were extracted with ethylacetate (2×200 mL). The combined organic layers were washed with brine(100 mL), dried over anhydrous sodium sulfate, filtered and the filtratewas concentrated under reduced pressure to provide crude compound. Thecrude product was purified by Combiflash™ chromatography eluting with35% EtOAc/hexanes to obtain the title compound (1 g, 37%) as a greysolid. ¹H NMR (DMSO-d₆) δ 9.97 (s, 1H), 9.06 (s, 1H), 8.45 (s, 1H), 8.13(s, 1H), 7.66 (s, 1H), 3.88 (s, 3H), 3.02 (m, 1H), 1.11 (d, 6H, J=7 Hz).LCMS: m/z=261.9 [M+H]⁺, RT=2.90 minutes, (Program P1, Column Y).

Step 4: 8-(Isobutyryl-methyl-amino)-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester

To a stirred solution of compound IV (1 g; 3.83 mmol; 1 eq) in dry DMF(10 mL) was added sodium hydride (60% in mineral oil, 0.13 g; 5.74 mmol;1.5 eq) in portions at 0° C. and the resulting mixture was stirred for 5min at 0° C. To the mixture was added methyl iodide (0.47 mL; 7.66 mmol;2 eq) and stirring was continued at 0° C. for 2 h. The temperature ofthe mixture was then slowly raised to 23° C. and the mixture was stirredfor another 2 h. The mixture was quenched with water (100 mL) and theorganic components were extracted with ethyl acetate (2×200 mL). Thecombined organic layers were washed with brine (100 mL), dried overanhydrous sodium sulfate, filtered and the solvent was removed underreduced pressure to provide crude compound (0.8 g, 76%) as a solid. Thecrude product was directly used in the next step without furtherpurification. ¹H NMR (DMSO-d₆) δ 9.37 (s, 1H), 8.20 (s, 1H), 7.71 (s,1H), 7.62 (s, 1H), 3.90 (s, 3H), 3.21 (s, 3H), 2.30 (m, 1H), 0.90 (m,6H). LCMS: m/z=276.2 [M+], RT=2.40 minutes, (Program P1, Column V).

Step 5:3-Bromo-8-(isobutyryl-methyl-amino)-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester

To a stirred solution of compound V (0.8 g, 2.9 mmol, 1 eq) in THF (20mL) was added N-bromosuccinamide (0.51 g, 2.9 mmol, 1 eq) at 0° C. andthe resulting mixture was stirred for 30 min. The mixture was quenchedwith water (100 mL) and the organic components were extracted with ethylacetate (2×200 mL). The combined organic layers were washed with brine(100 mL), dried over anhydrous sodium sulfate, filtered and solventswere removed under reduced pressure to provide crude compound. The crudeproduct was purified by flash chromatography using 100-200 mesh silicagel eluting with 30% EtOAc/hexanes to obtain the title compound (1 g,98%) as a brown solid. ¹H NMR (DMSO-d₆) δ 8.77 (s, 1H), 7.91 (s, 1H),7.77 (s, 1H), 3.93 (s, 3H), 3.21 (s, 3H), 2.38 (m, 1H), 090 (m, 6H).LCMS: m/z=354.0 [M+], 356.0 [M+2], RT=2.86 minutes; (Program P1, ColumnV).

Step 6:8-(Isobutyryl-methyl-amino)-3-(5-methyl-thiophen-2-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid methyl ester

To a stirred, dry DMF solution of compound VI (1 g; 2.82 mmol; 1 eq) ina reaction tube was added compound VIa (1.6 g; 4.23 mmol; 1.5 eq) andthe resulting mixture was degassed with argon for 5 min. To the mixturewas added Pd(PPh₃)₄ (0.32 g; 0.28 mmol; 0.1 eq) and degassing with argonwas repeated for about 5 min, then the reaction tube was sealed andheated at 140° C. for 2 h. The mixture was cooled to room temperature,quenched with water (100 mL) and the organic components were extractedwith ethyl acetate (2×200 mL). The combined organic layers were washedwith water (200 mL), brine and dried over anhydrous Na₂SO₄, thenfiltered. The filtrate was evaporated under vacuum to obtain a crudematerial which was purified by silica gel (230-400 mesh) columnchromatography eluting with 10-50% ethyl acetate/hexane to obtain thetitle compound (0.95 g, 91%) as an off white solid. ¹H NMR (DMSO-d₆) δ8.98 (s, 1H), 7.89 (s, 1H), 7.72 (s, 1H), 7.38 (d, 1H, J=3 Hz), 7.03 (d,1H, J=3 Hz), 3.90 (s, 3H), 3.23 (s, 3H), 2.55 (s, 3H), 2.50 (m, 1H),0.93 (m, 6H). LCMS: m/z=372.4 [M+], RT=3.24 minutes, (Program P1, ColumnV).

Step 7:8-(Isobutyryl-methyl-amino)-3-(5-methyl-thiophen-2-yl)-imidazo[1,2-a]pyridine-6-carboxylicacid

To a solution of compound VII (0.95 g, 2.56 mmol, 1 eq) inTHF:methanol:H₂O (40 mL, 5:1:1) at 23° C. was added a solution oflithium hydroxide monohydrate (0.16 g, 3.84 mmol, 1.5 eq) in water (5mL) and the resulting mixture was stirred at 23° C. for 1 h. The organicsolvent was removed under reduced pressure and the residue was dilutedwith water and acidified with 6N HCl to adjust the pH to about 5-6. Theprecipitated solid was collected by filtration and the solid was driedunder vacuum to afford the title compound (0.8 g, 82%) as an off whitesolid. ¹H NMR (DMSO-d₆) δ 13.5 (brs, 1H), 8.97 (s, 1H), 7.88 (s, 1H),7.69 (s, 1H), 7.37 (d, 1H, J=4 Hz), 7.02 (s, 1H), 3.23 (s, 3H), 2.55 (s,3H), 2.50 (m, 1H), 0.93 (m, 6H). LCMS: m/z=358.0 [M+], RT=2.35 minutes,(Program P1, Column Y).

Step 8:(S)—N-(1-(4H-1,2,4-Triazol-3-yl)ethyl)-8-(N-methylisobutyramido)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide

To a stirred solution of compound VIII (0.18 g, 0.50 mmol, 1 eq) in DMF(2 mL) were added TEA (0.21 mL, 1.51 mmol, 3 eq), a DMF (2 mL) solutionof (S)-1-(4H-[1,2,4]triazol-3-yl)-ethylamine hydrochloride (0.09 g, 0.60mmol; 1.2 eq) and T3P (0.23 mL, 0.75 mmol, 1.5 eq) at 23° C. and theresulting mixture was stirred at 120° C. for 2 h. The mixture was cooledto room temperature and quenched with water. The organic components wereextracted with ethyl acetate (2×100 mL) and the combined extracts werewashed with brine. The organic layer was dried over anhydrous sodiumsulfate, filtered and concentrated to dryness to provide crude materialwhich was purified by silica gel (100-200 mesh) column chromatographyeluting with 0-5% methanol/CH₂Cl₂ to obtain the title compound (0.12 g,53%) as an off white solid. ¹H NMR (DMSO-d₆) δ 13.85 (brs, 1H), 9.13(brs, 1H), 9.01 (s, 1H), 8.48 (s, 1H), 7.84 (m, 2H), 7.40 (m, 1H), 7.02(s, 1H), 5.32 (m, 1H), 3.17 (s, 3H), 2.54 (s, 3H), 2.43 (m, 1H), 1.55(m, 3H), 0.95 (m, 6H). LCMS: m/z=452.3 [M+], RT=2.61 minutes, (ProgramP1, Column V).

TABLE 1 Prepared by method of Ex. No. Structure LCMS Example No. 1

449.2 [M + H]⁺ 1 2

457.2 [M + H]⁺ 2 3

448.2 [M + H]⁺ 3 4

470.2 [M + H]⁺ 4 5

482.2 [M + H]⁺ 5 6

457.0 [M + H]⁺ 6 7

444.0 [M + H]⁺ 7 8

433.2 [M + H]⁺ 8 9

409.6 [M + H]⁺ 9 10

428.4 [M + H]⁺ 10 11

450.0 [M + H]⁺ 11 12

493.4 [M + H]⁺ 12 13

490.2 [M + H]⁺ 13 14

471.0 [M + H]⁺ 14 15

444.4 [M + H]⁺ 15 16

471.0 [M + H]⁺ 16 17

461.2 [M + H]⁺ 17 18

481.0 [M + H]⁺ 18 19

486.3 [M +H]+ 19 20

452.3 [M + H]⁺ 20 21

459.4 [M + H]⁺ 1 22

458.0 [M + H]⁺ 4 23

448.4 [M + H]⁺ 4 24

458.8 [M + H]⁺ 4 25

470.0 [M + H]⁺ 4 26

488.1 [M + H]⁺ 4 27

480.2 [M + H]⁺ 4 28

444.2 [M + H]⁺ 4 29

434.2 [M +H]⁺ 4 30

498.0 [M + H]⁺ 4 31

481.4 [M + H]⁺ 4 32

481.2 [M + H]⁺ 4 33

459.2 [M + H]⁺ 4 34

460.0 [M + H]⁺ 4 35

497.2 [M + H]⁺ 4 36

481.2 [M + H]⁺ 4 37

462.2 [M + H]⁺ 4 38

490.2 [M + H]⁺ 4 39

499.1 [M + H]+ 4 40

473.4 [M + H]⁺ 4 41

471.4 [M + H]⁺ 4 42

487.2 [M + H]⁺ 4 43

474.2 [M + H]⁺ 4 44

515.0 [M + H]⁺ 4 45

472.2 [M + H]⁺ 4 46

476.2 [M + H]⁺ 4 47

482.2 [M + H]⁺ 4 48

464.0 [M + H]⁺ 4 49

485.2 [M + H]⁺ 4 50

471.0 [M + H]⁺ 4 51

481.0 [M + H]⁺ 4 52

484.0 [M + H]⁺ 4 53

471.0 [M + H]⁺ 4 54

498.2 [M + H]⁺ 4 55

486.2 [M + H]⁺ 4 56

499.2 [M + H]⁺ 4 57

477.2 [M + H]⁺ 4 58

462.2 [M + H]⁺ 4 59

524.2 [M + H]⁺ 4 60

454.2 [M + H]⁺ 4 61

476.2 [M + H]⁺ 4 62

432.2 [M + H]⁺ 4 63

462.0 [M + H]⁺ 4 64

474.2 [M + H]⁺ 4 65

465.0 [M + H]⁺ 4 66

482.0 [M + H]⁺ 4 67

490.2 [M + H]⁺ 4 68

500.0 [M + H]⁺ 4 69

496.1 [M + H]⁺ 4 70

484.4 [M + H]⁺ 4 71

496.2 [M + H]⁺ 4 72

495.1 [M + H]⁺ 4 73

476.2 [M + H]⁺ 4 74

462.4 [M + H]⁺ 4 75

460.4 [M + H]⁺ 4 76

504.2 [M + H]⁺ 4 77

482.6 [M + H]⁺ 4 78

465.4 [M + H]⁺ 4 79

508.2 [M + H]⁺ 4 80

513.2 [M + H]⁺ 4 81

502.2 [M + H]⁺ 4 82

514.1 [M + H]⁺ 4 83

496.2 [M + H]⁺ 4 84

496.2 [M + H]⁺ 4 85

485.2 [M + H]⁺ 4 86

516.1 [M + H]⁺ 4 87

495.2 [M + H]⁺ 4 88

463.2 [M + H]⁺ 4 89

470.2 [M + H]⁺ 7 90

470.2 [M + H]⁺ 7 91

454.2 [M + H]⁺ 7 92

451.2 [M + H]⁺ 7 93

477.2 [M + H]⁺ 7 94

465.0 [M + H]⁺ 7 95

462.2 [M + H]⁺ 7 96

474.4 [M + H]⁺ 7 97

454.0 [M + H]⁺ 8 98

443.2 [M + H]⁺ 8 99

459.2 [M + H]⁺ 8 100

433.0 [M + H]⁺ 8 101

449.0 [M + H]⁺ 8 102

448.0 [M + H]⁺ 8 103

447.0 [M + H]⁺ 8 104

473.4 [M + H]⁺ 8 105

465.0 [M + H]⁺ 8 106

458.0 [M + H]⁺ 8 107

468.0 [M + H]⁺ 8 108

462.2 [M + H]⁺ 8 109

449.2 [M + H]⁺ 8 110

447.2 [M + H]⁺ 8 111

458.2 [M + H]⁺ 8 112

476.4 [M + H]⁺ 8 113

447.0 [M + H]⁺ 8 114

454.0 [M + H]⁺ 10 115

460.2 [M + H]⁺ 11 116

461.4 [M + H]⁺ 11 117

476.4 [M + H]⁺ 11 118

470.2 [M + H]⁺ 11 119

496.2 [M + H]⁺ 11 120

476.4 [M + H]⁺ 11 121

450.6 [M + H]⁺ 11 122

490.4 [M + H]⁺ 11 123

498.2 [M + H]⁺ 11 124

530.2 [M + H]⁺ 11 125

477.2 [M + H]⁺ 11 126

490.6 [M + H]⁺ 11 127

480.2 [M + H]⁺ 11 128

476.3 [M + H]⁺ 11 129

464.0 [M + H]⁺ 11 130

472.2 [M + H]⁺ 11 131

530.0 [M + H]⁺ 11 132

494.2 [M + H]⁺ 11 133

468.2 [M + H]⁺ 11 134

504.2 [M + H]⁺ 11 135

436.4 [M + H]⁺ 11 136

472.0 [M + H]⁺ 11 137

454.2 [M + H]⁺ 11 138

451.8 [M + H]⁺ 11 139

480.2 [M + H]⁺ 11 140

466.0 [M + H]⁺ 11 141

466.2 [M + H]⁺ 11 142

466.1 [M + H]⁺ 11 143

471.2 [M + H]⁺ 11 144

486.2 [M + H]⁺ 11 145

500.0 [M + H]⁺ 11 146

480.0 [M + H]⁺ 11 147

462.4 [M + H]⁺ 11 148

503.2 [M + H]⁺ 12 149

444.4 [M + H]⁺ 15 150

470.4 [M + H]⁺ 15 151

473.0 [M + H]⁺ 16 152

527.4 [M + H]⁺ 16 153

459.4 [M + H]⁺ 16 154

485.2 [M + H]⁺ 16 155

485.2 [M + H]⁺ 16 156

485.4 [M + H]⁺ 16 157

445.2 [M + H]⁺ 16 158

473.2 [M + H]⁺ 16 159

474.2 [M + H]⁺ 16 160

486.4 [M + H]⁺ 16 161

501.4 [M + H]⁺ 16 162

460.2 [M + H]⁺ 16 163

500.8 [M + H]⁺ 16 164

485.8 [M + H]⁺ 16 165

475.4 [M + H]⁺ 16 166

475.2 [M + H]⁺ 16 167

461.3 [M + H]⁺ 16 168

471.2 [M + H]⁺ 18 169

498.0 [M + H]⁺ 18 170

491.3 [M + H]⁺ 18 171

485.2 [M + H]⁺ 18 172

483.2 [M + H]⁺ 18 173

482.0 [M + H]⁺ 18 174

505.0 [M + H]⁺ 18 175

481.0 [M + H]⁺ 18 176

502.0 [M + H]⁺ 18 177

482.0 [M + H]⁺ 18 178

449.0 [M + H]⁺ 18 179

463.0 [M + H]⁺ 18 180

486.0 [M + H]⁺ 18 181

503.2 [M + H]⁺ 18 182

485.2 [M + H]⁺ 18 183

466.4 [M + H]⁺ 18 184

505.2 [M + H]⁺ 18 185

483.0 [M + H]⁺ 18 186

500.1 [M + H]⁺ 19 187

438.0 [M + H]⁺ 20 188

464.2 [M + H]⁺ 20

Example 189 In Vitro Studies

A. Cloning

The FLIPR® assay utilizes cells which express human or rat P2X3 orP2X2/3 receptors. Recombinant cells expressing hP2X3 (Cat #6188) andhP2X2/3 (Cat #6179) were procured from Chantest Corp. Rat P2X2 (NCBIAccession No: U14414) was amplified by PCR from PC12 cDNA (a rat adrenalmedulla cell line). The PCR product obtained containing the proteincoding sequence of rat P2X2 was cloned into EcoRV-digested anddephosphorylated vector pIRES-puro3 within the multiple cloning site(MCS). See, FIG. 1A.

Rat P2X3 (NCBI Accession No: X91167) was amplified by PCR from rat braincDNA. The PCR product obtained containing the protein coding sequence ofrat P2X3 was cloned into EcoRV-digested and dephosphorylated vectorpCDNA-Hygro within the multiple cloning site (MCS) (FIG. 1B). Rat P2X3cloned into pcDNA-Hygro was then subcloned into pcDNA-5/TO at HindIII(5′) and XhoI (3′) sites within the multiple cloning site (MCS) of thevector (FIG. 1C).

All the constructs yielding the recombinant vector DNA were used fortransfection and generation of the cell lines, after sequenceverification.

B. Development of Recombinant TRex293 Cells Expressing rP2X2/3 andCHO-TRex Cells Expressing rP2X3

Transfection was carried out using super-coiled constructs (purifiedusing QIAGEN kit) in antibiotic free, serum free DMEM usingLipofectamine® 2000 (Invitrogen) transfection agent. The DNA constructsrat P2X2 in pIRES-Puro3 and rat P2X3 in pCDNA5/TO were co-transfectedinto TRex293 cells in order to generate the rP2X2/3 stable line. 50μg/mL hygromycin (Invitrogen) and 0.5 μg/mL puromycin (Fermentek) wereused for selection of stable clones of rP2X2/3. Rat P2X3 in pCDNAS/TODNA construct was transfected to CHO-TRex cells to generate the rP2×3stable line and 500 μg/mL hygromycin (Invitrogen) was used as selectionantibiotic. Transfected stable colonies were then functionally verifiedand robust clones suitable for assay were clonally purified throughdilutions.

C. Assay Protocols

(i) Intracellular Calcium Assay Protocol for Screening Compounds

Cryo-vial containing 6×10⁶ cells (human P2X3-HEK/humanP2X2/3-TRex293/rat P2X2/3-TRex293/rat P2X3 TRex-CHO) was thawed in a 37°C. water bath. Cells were suspended in 20 mL of respective cell platingmedia (See annexure for composition) in a 50 mL centrifuge tube. Thecell viability was checked with the help of Trypan Blue dye. Uponwashing, cells were plated in a black 384-well clear bottomed, sterilepoly-D-lysine coated plate such that, each well contained 10,000 cells(15,000/well for hP2X3) in 30 μL cell plating media. The plate wasincubated in a 5% CO₂ incubator at 37° C. for 24 h.

The next day, prior to the assay, the cell plating media was removedfrom each well by decanting and gentle tapping. Thirty μL of FLIPRCalcium 4 dye solution was added to each well. The plate was incubatedat 37° C. for 45 min (60 min for hP2X3). The plate was next equilibratedat room temperature for 15 minutes before placing it in a 384 well FLIPRfor the assay.

Compounds were dissolved in DMSO and serially diluted following 11 pointhalf log (3.16 fold) dilution with a starting concentration of 2 mM.Dilutions were mixed with assay buffer just before performing the assay.

Compounds were added to the respective wells of the assay-ready cellplate with the help of the FLIPR and fluorescence readings were capturedfor 5 min to observe any possible agonistic property of the compounds.The plate was then incubated at room temperature for 15 min. The cellswere stimulated with respective agonist EC₇₅ concentration and thefluorescence readings were captured for another 5 min by FLIPR. Thedifference in fluorescence readings in presence of the compounds werecompared with that of the control wells (wells having no compound) tocalculate the inhibitory potency of the compounds. The IC₅₀ values ofthe compounds were determined using the Graph pad Prism software.

(ii) Cell Plating Media for hP₂X₃-HEK and hP₂X_(2/3)-TRex293 Cells

-   -   DMEM/F12(1:1) HAM media (Invitrogen; Cat #11039)    -   1×NEAA (Invitrogen; Cat #11140)    -   25 mM HEPES (Invitrogen; Cat #15630)    -   1 mM sodium pyruvate (Invitrogen; Cat #11360)    -   10% tetracycline negative FBS (PAA; Cat# A15-209)    -   1 μg/mL doxycycline (Clontech; Cat #63131) [for hP2X2/3-TRex293        cells only]

(iii) Cell Plating Media for rP₂X_(2/3)-TRex293 Cells

-   -   DMEM media (Invitrogen; Cat #11965)    -   25 mM HEPES (Invitrogen; Cat #15630)    -   10% tetracycline negative FBS (PAA; Cat# A15-209)    -   1 μg/mL Doxycycline (Clontech; Cat #63131)

(iv) Cell Plating Media for rP₂X₃-CHOTRex Cells

-   -   F-12 nutrient mixture (HAM) 1× (Invitrogen; Cat #11765)    -   1× Glutamax™ (Invitrogen; Cat #35050)    -   10% tetracycline negative FBS (PAA; Cat# A15-209)    -   1 μg/mL doxycycline (Clontech; Cat #63131)

(v) Assay Buffer Composition

-   -   HBSS (Invitrogen Cat #14025)    -   20 mM HEPES (Invitrogen Cat #15630)    -   0.01% F127 (Sigma Cat# P2443)    -   1.8 mM CaCl₂ (Sigma Cat# C5080)    -   pH adjusted to 7.4

(vi) Dye Solution Composition

-   -   1×FLIPR Calcium 4 dye in assay buffer (Molecular devices Cat#        R8141)    -   1.8 mM Probenecid (Sigma Cat# P8761)    -   pH adjusted to 7.4

Data from the P2X₃ and P2X_(2/3) FLIPR assays for Examples 1-188 areshown in Table 2.

TABLE 2 Example P2X₃ P2X_(2/3) 1 B C 2 D B 3 C B 4 A A 5 B B 6 D B 7 A B8 A B 9 C C 10 B C 11 A B 12 A A 13 D B 14 A B 15 B C 16 D B 17 B B 18 AA 19 A A 20 A B 21 A B 22 A A 23 A B 24 A A 25 A A 26 A A 27 A A 28 A A29 A B 30 A A 31 A A 32 A A 33 A A 34 A A 35 A A 36 A A 37 A A 38 A A 39A A 40 D A 41 A A 42 A A 43 A A 44 A A 45 D A 46 A A 47 A A 48 A A 49 DA 50 A B 51 B C 52 A A 53 A A 54 A A 55 D B 56 A B 57 A B 58 A A 59 B C60 A A 61 A A 62 A B 63 A A 64 A B 65 A A 66 B B 67 A A 68 A B 69 A B 70A A 71 A B 72 A A 73 B B 74 B C 75 A B 76 A A 77 A B 78 A A 79 A A 80 AA 81 A A 82 A B 83 A A 84 A A 85 A A 86 B B 87 B B 88 D A 89 A B 90 A C91 B C 92 B C 93 B C 94 A C 95 A D 96 B B 97 A B 98 C B 99 A C 100 A B101 A A 102 A A 103 A B 104 A B 105 A B 106 D A 107 A A 108 A A 109 A B110 A A 111 D A 112 B C 113 A B 114 A V 115 C B 116 C B 117 A A 118 B B119 A B 120 A A 121 B B 122 A A 123 D A 124 B B 125 B B 126 D A 127 D A128 A B 129 A B 130 A A 131 A B 132 A A 133 A B 134 A C 135 B B 136 A B137 A B 138 A B 139 A B 140 A B 141 A B 142 A B 143 C B 144 B A 145 C B146 A B 147 C B 148 A A 149 B C 150 A B 151 A B 152 D B 153 D A 154 B B155 D A 156 D A 157 A B 158 D A 159 B C 160 D B 161 D A 162 A C 163 D A164 D A 165 A A 166 A A 167 A B 168 A A 169 A A 170 A A 171 A A 172 A A173 B B 174 A A 175 B C 176 B B 177 A A 178 A B 179 A A 180 A A 181 A A182 A A 183 B B 184 A A 185 B C 186 D A 187 A B 188 A B A: IC₅₀ = 1-100nM B: IC₅₀ = >100-1000 nM C: IC₅₀ = >1000-10,000 nM D: IC₅₀ >10,000 nM

Example 190 In Vivo Thermal Hyperalgesia (Hargreaves Test) Studies inthe Rat

Male Sprague Dawley rats of young adult age group and body weight rangeof 180-200 g were included in the study. Animals were housed under a 12h light/dark cycle with food and water ad libitum. The animals underwentacclimatization with the observation chambers of the Hargreaves'apparatus for two days, twice daily for 45-60 min each time prior toinitiation of study. Animals were also habituated to the apparatus for15-30 min before each testing. Thermal hyperalgesia was assessed usingthe rat plantar test (Ugo Basile, Italy) following a modified method ofHargreaves (1988, “A new and sensitive method for measuring thermalnociception in cutaneous hyperalgesia”, Pain 32: 77-88).

For measurement of Paw withdrawal latency (PWL) values the rats wereexposed to a mobile infrared heat source applied directly below theplantar surface of the rat hind paw. The paw withdrawal latency (PWL)was defined as the time in seconds taken by the rat to remove its hindpaw from the heat source. Thirty three percent IR of the instrument wasused to measure PWL. Animals showing basal response between 8-14 sec onan untreated paw were included in the study. A cut off point of 20 secwas used to prevent tissue damage.

Following basal readout of PWL values to the thermal stimulus (PWLmeasurements described previously), 50 μL of complete Freund's Adjuvant(CFA—1 mg/mL suspension—Sigma, USA, Cat # F5881) was injectedsubcutaneously into the plantar surface of the right hind (ipsilateral)paw of animals under light isoflurane anesthesia. A one mL syringe and26 g^(1/2)-inch needle was used for the injection. CFA suspension wasmixed thoroughly before each injection. Light pressure was applied tothe injection site for 10 s immediately after the needle was removedfrom the paw to prevent any leaking out of adjuvant oil from theinjection site. The rats were then returned to their housing to recoverand kept in soft bedding.

Next day (day 1) after 20-22 h of CFA injection, PWL of animals wererecorded. Mean of three readings are taken as PWL recording ofipsilateral paw of each animal for pre and post CFA basal readout.Animals with PWL values of <6 sec on day 1 post CFA injection wereconsidered hyperalgesic and selected for randomization into treatmentgroups and further test sessions following a single blind protocol.

In the test session, PWL was assessed at 1 h post oral dosing of CE testarticle, vehicle (20% polyethylene glycol, 1% Tween™ 80, 79% water) andnaproxen (positive control). See, e.g., FIG. 2 (compound of Example 22),FIG. 5 (compound of Example 38) and FIG. 6 (compound of Example 52).

Statistical analysis was done with One way ANOVA followed by Dunnett'smultiple comparison post test. Post treatment PWL values were comparedwith pre treatment PWL values and p<0.05 was considered statisticallysignificant. Each group comprised of 8 animals.

Example 191 Formalin Induced Pain (Automated Nociception Analyzer Test)in the Rat

Male Sprague Dawley rats of young adult age group and body weight rangeof 200-250 g were included in the study. Animals were housed under a 12h light/dark cycle with food and water ad libitum. Animals wereacclimatized in the observation chambers of Automated NociceptionAnalyzer (ANA) for 45-60 min, twice daily for two days prior to thestudy day. On the day of the study, metal bands were glued to theplantar surface of the right hind paw of each animal enrolled in thestudy set and kept in plastic observation chambers for 10-15 min.Formalin injection was done in the animals after 0.5 or 1 h of oraltreatment with test compound or vehicle (20% polyethylene glycol, 1%Tween™ 80 reagent, 79% water). Formalin injection of the animals wasdone with 50 μL of 2.5% formalin (freshly prepared from formaldehydesolution, Sigma, USA, Cat # F8775) injected subcutaneously in to thedorsum of right hind paw. Animals were placed back to their respectiverecording chambers of ANA immediately after injection. Flinch count datafor each animal was recorded from 1 to 60 min post formalin injection,using ANA motion analysis software. The study was analyzed in 2 phases,the early phase extended from 0-10 min and second phase extended from11-60 min post formalin injection. The data was collected in 5 min timebins and the counts of each bin were added up for total count of thephase. See, e.g., FIG. 3 (test compound of Example 22).

Statistical analysis was done with unpaired t test. Comparison was donebetween total count of treatment groups and vehicle group and p<0.05 wasconsidered statistically significant. Eight animals were typically usedin each of test article and vehicle treated groups.

Example 192 Acetic Acid Induced Writhing Test in Mice

Swiss albino mice of 30-40 g were included in the study. The mice weregiven an intraperitoneal injection of 0.7% v/v acetic acid solution atan injection volume of 10 mL/kg, 30 min after oral administration ofvehicle or test article control. Test articles were administered,typically, at doses between 20 and 60 mg/kg. The mice were placedindividually into glass chambers. The number of writhes produced inthese animals was counted for 15 min following acetic acidadministration. For scoring purposes writhing was indicated bystretching of the abdomen with simultaneous stretching of at least onehind limb. See, e.g., FIG. 4.

Statistical analysis was done with One way ANOVA followed by Dunnett'smultiple comparison tests. Comparison was done between treatment groupsand vehicle with respect to total number of writhes and p<0.05 wasconsidered statistically significant. Each group comprised of 6 animals.

All publications cited in this specification are incorporated herein byreference. While the invention has been described with reference toparticular embodiments, it will be appreciated that modifications can bemade without departing from the spirit of the invention. Suchmodifications are intended to fall within the scope of the appendedclaims.

What is claimed is:
 1. A method for regulating one or both of the P2X₃or P2X_(2/3) receptors in airway tissues, comprising administering to apatient in need thereof an effective amount of a compound of formula(I):

or a pharmaceutically acceptable salt or prodrug thereof, wherein: R¹ isoptionally substituted heteroaryl or NR⁵R⁶; R² is optionally substitutedaryl, optionally substituted heteroaryl, C₁ to C₆ alkyl, or S—C₁ to C₆alkyl; R³ is H or C₁ to C₆ alkyl; R⁴ is optionally substitutedheteroaryl; R⁵ and R⁶ are, independently, selected from the groupconsisting of H, optionally substituted C₁ to C₆ alkyl, C₃ to C₆cycloalkyl, optionally substituted aryl, optionally substitutedheteroaryl, and CO(C₁ to C₆ alkyl); or R⁵ and R⁶ are joined to form a 5or 6-membered heterocyclic ring optionally substituted by one or more ofhalogen, C₁ to C₆ alkyl, C₁ to C₆ alkoxy, C₁ to C₆ hydroxyalkyl, C₃ toC₆ cycloalkyl, C₁ to C₆ alkyl containing 1 to 3 fluorine atoms, C₃ to C₆cycloalkyl-C₁ to C₆ alkyl, or CONH₂.
 2. The method according to claim 1,wherein the compound is of formula (V):

or a pharmaceutically acceptable salt or prodrug thereof, wherein: eachX is independently selected from the group consisting of C, CH, CR⁷, N,NH, NR⁷, O and S, and at least one X is N, NH, NR⁷, O or S and at leastone X is C or CR⁷; R²-R⁴ are defined above; and R⁷ is halogen, C₁ to C₆alkyl, C₃ to C₆ cycloalkyl, C₃ to C₆ cycloalkyl-C₁ to C₆ alkyl, C₁ to C₆hydroxyalkyl, C₁ to C₆ alkoxy, C₁ to C₆ alkyl containing 1 to 3 fluorineatoms, or CH₂CONH₂.
 3. The method of claim 1, wherein the compound is offormula (VI):

or a pharmaceutically acceptable salt or prodrug thereof, wherein: R²-R⁶are defined above.
 4. The method according to claim 1, wherein R² isoptionally substituted aryl.
 5. The method according to claim 1, whereinR² is optionally substituted phenyl.
 6. The method according to claim 1,wherein R² is phenyl substituted with one or more C1 to C6 alkyl.
 7. Themethod according to claim 1, wherein R² is phenyl substituted with oneCH₃.
 8. The method according to claim 1, wherein R² is 2-tolyl or3-tolyl.
 9. The method according to claim 1, wherein R² is C₁ to C₆alkyl.
 10. The method according to claim 1, wherein R² is butyl.
 11. Themethod according to claim 1, wherein R² is —S—(C₁ to C₆ alkyl).
 12. Themethod according to claim 1, wherein R² is SCH₂CH₂CH₃.
 13. The methodaccording to claim 1, wherein R² is optionally substituted heteroaryl.14. The method according to claim 1, wherein R² is heteroarylsubstituted with one or more halogen, cyano, C₁ to C₆ alkyl, or C₁ to C₆alkyl containing 1-3 fluorine atoms.
 15. The method according to claim1, wherein R² is thiazole, thiophene, or furan.
 16. The method accordingto claim 1, wherein R² is thiazole substituted with C₁ to C₆ alkyl. 17.The method according to claim 1, wherein R² is thiophene substitutedwith one or more of halogen, cyano, C₁ to C₆ alkyl, or C₁ to C₆ alkylcontaining 1-3 fluorine atoms.
 18. The method according to claim 1,wherein R² is furan substituted with C₁ to C₆ alkyl.
 19. The methodaccording to claim 1, wherein R² is 2-chloro-thiophene,2-methyl-thiophene, 2-cyano-thiophene, 2-trifluoromethyl-thiophene,5-methyl-thiazole, 2-methyl-thiazole, or 2-methyl-furan.
 20. The methodaccording to claim 1, wherein R⁴ is optionally substituted triazole,optionally substituted pyridine, optionally substituted pyridone,optionally substituted oxadiazole, optionally substituted pyrazine, oroptionally substituted pyrimidine.
 21. The method according to claim 1,wherein R⁴ is heteroaryl optionally substituted with C₁ to C₆ alkyl, C₃to C₆ cycloalkyl, C₁ to C₆ alkoxy, or C₁ to C₆ trifluoroalkyl.
 22. Themethod according to claim 1, wherein R⁴ is pyridine substituted with oneor more C₁ to C₆ alkyl, C₃ to C₆ cycloalkyl, C₁ to C₆ alkoxy, or C₁ toC₆ trifluoroalkyl.
 23. The method according to claim 1, wherein R⁴ ispyridine and the nitrogen atom of said pyridine is bound to an O-atom.24. The method according to claim 1, wherein R⁴ is pyrazine substitutedwith one or more C₁ to C₆ alkyl.
 25. The method according to claim 1,wherein R⁴ is pyrimidine substituted with one or more C₁ to C₆ alkyl orC₁ to C₆ alkoxy.
 26. The method according to claim 1, wherein R⁴ ispyridone substituted with one or more C₁ to C₆ alkyl.
 27. The methodaccording to claim 1, wherein R⁴ is 1,2,4-triazole, 2-methyl-pyridine,2-methoxy-pyridine, 1-oxo-pyridine, 1-oxo-2-methyl-pyridine,1-oxo-2-trifluoromethyl-pyridine, 2-trifluoromethyl-pyridine,2-cyclopropyl-pyridine, 1,3,4-oxadiazole, 1,2,4-oxadiazole,3-methyl-1,2,4-oxadiazole, 2-methyl-1,3,4-oxadiazole, 2-methyl-pyrazine,2-methyl-pyrimidine, 2-methoxy-pyrimidine, or 1-methyl-pyridone.
 28. Themethod according to claim 1, wherein one or both of R⁵ and R⁶ areoptionally substituted phenyl.
 29. The method according to claim 1,wherein one or both of R⁵ and R⁶ are phenyl substituted with fluorine orC₁ to C₆ alkoxy.
 30. The method according to claim 1, wherein one orboth of R⁵ and R⁶ are optionally substituted thiazole.
 31. The methodaccording to claim 1, wherein one or both of R⁵ and R⁶ are optionallysubstituted C₁ to C₆ alkyl or C₃ to C₆ cycloalkyl.
 32. The methodaccording to claim 1, wherein one or both of R⁵ and R⁶ are4-fluoro-phenyl or 2-methoxy-phenyl.
 33. The method according to claim1, wherein R⁵ and R⁶ are joined to form an optionally substitutedheteroaryl or an optionally substituted 5 or 6-membered heterocyclicring.
 34. The method according to claim 1, wherein R⁵ and R⁶ are joinedto form an optionally substituted pyrrolidine, piperazine or piperidine.35. The method according to claim 1, wherein R⁵ and R⁶ are joined toform an optionally substituted imidazole, pyrazole, tetrazole, ortriazole.
 36. The method according to claim 1, wherein R⁵ and R⁶ arejoined to form pyrrolidine optionally substituted with one or more C₁ toC₆ alkyl or C₁ to C₆ alkoxy.
 37. The method according to claim 1,wherein R⁵ and R⁶ are joined to form imidazole substituted with one ormore C₁ to C₆ alkyl.
 38. The method according to claim 1, wherein R⁵ andR⁶ are joined to form a pyrazole substituted with one or more C₁ to C₆alkyl.
 39. The method according to claim 1, wherein R⁵ and R⁶ are joinedto form tetrazole substituted with one or more C₃ to C₆ cycloalkyl, C₁to C₆ alkyl, C₁ to C₆ hydroxyalkyl, C₁ to C₆ alkyl containing 1-3fluorine atoms, and C₃ to C₆ cycloalkyl-C₁ to C₆ alkyl.
 40. The methodaccording to claim 1, wherein R⁵ and R⁶ are joined to form triazolesubstituted with one or more C₃ to C₆ cycloalkyl, C₁ to C₆ alkylcontaining 1-3 fluorine atoms, and C₁ to C₆ alkyl.
 41. The methodaccording to claim 1, wherein R⁵ and R⁶ are joined to form a piperidinesubstituted with one or more C₁ to C₆ alkoxy, halogen, C₁ to C₆ alkylcontaining 1-3 fluorine atoms, C₁ to C₆ alkyl, or CONH₂.
 42. The methodaccording to claim 1, wherein R⁵ and R⁶ are joined to form a piperazinesubstituted with one CONH₂.
 43. The method according to claim 1, whereinR⁵ and R⁶ are joined to form 3-methoxy-pyrrolidine,3-methyl-3-methoxy-pyrrolidine, 2,5-dimethyl-imidazole,5-ethyl-pyrazole, 5-propyl-tetrazole, 5-cyclopropyl-tetrazole,5-propyl-tetrazole, 5-isopropyl-tetrazole, 5-ethyl-tetrazole,5-cyclobutyl-tetrazole, 5-cyclopropylmethyl-tetrazole,5-methyl-tetrazole, 5-hydroxymethyl-tetrazole,5-difluoromethyl-tetrazole, 5-(2,2,2-trifluoroethyl)-tetrazole,5-(1,1-difluoroethyl)-tetrazole, 5-cyclopropyl-triazole,5-difluoromethyl-triazole, 5-trifluoromethyl-triazole,5-methyl-triazole, 5-isopropyl-triazole, 5-propyl-triazole,5-ethyl-triazole, 5-tert-butyl-triazole, 5-cyclobutyl-triazole,5-(1,1-difluoroethyl)-triazole, 5-(2,2,2-trifluoroethyl)-triazole,3,5-dimethyl-1,2,4-triazole, 4-methyl-piperidine,4,4-dimethyl-piperidine, 4,4-difluoro-piperidine,4-methyl-4-carboxamido-piperidine, 4-fluoro-piperidine,4-trifluoromethyl-piperidine, 4-fluoromethyl-piperidine,4-methyl-4-methoxy-piperidine, 4-methoxy-piperidine, or3-methoxy-piperidine, or 4-carboxamido-piperazine.
 44. The methodaccording to claim 1, wherein the compound is selected from the groupconsisting of(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(5-ethyl-1,3,4-oxadiazol-2-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(2,5-dimethyl-1H-imidazol-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(3,5-dimethyl-4H-1,2,4-triazol-4-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(5-(difluoromethyl)-1H-1,2,3-triazol-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-(difluoromethyl)-1H-1,2,3-triazol-1-yl)-3-(5-methyl-1,3,4-thiadiazol-2-yl)-N-((6-methylpyridin-3-yl)methyl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-ethyl-1H-pyrazol-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-3-(5-methylthiophen-2-yl)-8-(phenylamino)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(1-methyl-1H-pyrazol-4-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-3-butyl-8-(4-methylpiperidin-1-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(4-methylpiperidin-1-yl)-3-(propylthio)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(4-methylpiperidin-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(4-carbamoyl-4-methylpiperidin-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(4-carbamoylpiperazin-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide(S)—N-(1-(1,3,4-oxadiazol-2-yl)ethyl)-8-(5-(difluoromethyl)-1H-1,2,3-triazol-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(4-methylpiperidin-1-yl)-3-(o-tolyl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-cyclopropyl-1H-tetrazol-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-(hydroxymethyl)-1H-tetrazol-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-(difluoromethyl)-1H-tetrazol-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(R)-8-(5-(difluoromethyl)-1H-tetrazol-1-yl)-N-(1-(3-methyl-1,2,4-oxadiazol-5-yl)ethyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(N-methylisobutyramido)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-ethyl-1,3,4-oxadiazol-2-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-ethyl-1H-1,2,3-triazol-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(5-ethyl-1H-1,2,3-triazol-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-ethyl-1H-1,2,3-triazol-1-yl)-N-((5-methylpyrazin-2-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-cyclopropyl-1H-1,2,3-triazol-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-3-(5-methylthiophen-2-yl)-8-(5-(trifluoromethyl)-1H-1,2,3-triazol-1-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-(difluoromethyl)-1H-1,2,3-triazol-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-methyl-1H-1,2,3-triazol-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(5-methyl-1H-1,2,3-triazol-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)-8-(5-(trifluoromethyl)-1H-1,2,3-triazol-1-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-(difluoromethyl)-1H-1,2,3-triazol-1-yl)-N-((2-methylpyrimidin-5-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-(difluoromethyl)-1H-1,2,3-triazol-1-yl)-N-((5-methylpyrazin-2-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-ethyl-1H-1,2,3-triazol-1-yl)-N-((2-methylpyrimidin-5-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(5-cyclopropyl-1H-1,2,3-triazol-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-(difluoromethyl)-1H-1,2,3-triazol-1-yl)-N-((2-methoxypyrimidin-5-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-(difluoromethyl)-1H-1,2,3-triazol-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiazol-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(5-isopropyl-1H-1,2,3-triazol-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-3-(5-chlorothiophen-2-yl)-8-(5-(difluoromethyl)-1H-1,2,3-triazol-1-yl)imidazo[1,2-a]pyridine-6-carboxamide,N-((2-methylpyrimidin-5-yl)methyl)-3-(5-methylthiophen-2-yl)-8-(5-(trifluoromethyl)-1H-1,2,3-triazol-1-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-isopropyl-1H-1,2,3-triazol-1-yl)-N-((2-methylpyrimidin-5-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-cyclopropyl-1H-1,2,3-triazol-1-yl)-N-((2-methylpyrimidin-5-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-cyclopropyl-1H-1,2,3-triazol-1-yl)-N-((2-methoxypyrimidin-5-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(5-cyclobutyl-1H-1,2,3-triazol-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,N-((2-methoxypyrimidin-5-yl)methyl)-3-(5-methylthiophen-2-yl)-8-(5-(trifluoromethyl)-1H-1,2,3-triazol-1-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-isopropyl-1H-1,2,3-triazol-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(5-(tert-butyl)-1H-1,2,3-triazol-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-(difluoromethyl)-1H-1,2,3-triazol-1-yl)-N-((2-methylpyrimidin-5-yl)methyl)-3-(5-methylthiazol-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-(difluoromethyl)-1H-1,2,3-triazol-1-yl)-3-(5-methylfuran-2-yl)-N-((6-methylpyridin-3-yl)methyl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-cyclobutyl-1H-1,2,3-triazol-1-yl)-N-((2-methylpyrimidin-5-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(1,3,4-oxadiazol-2-yl)ethyl)-8-(5-(difluoromethyl)-1H-1,2,3-triazol-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-3-(5-cyanothiophen-2-yl)-8-(5-(difluoromethyl)-1H-1,2,3-triazol-1-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)propyl)-8-(5-(difluoromethyl)-1H-1,2,3-triazol-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(5-(difluoromethyl)-1H-1,2,3-triazol-1-yl)-3-(5-methylthiazol-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)-8-(5-(difluoromethyl)-1H-1,2,3-triazol-1-yl)-N-(2-methyl-1-(4H-1,2,4-triazol-3-yl)propyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-cyclobutyl-1H-1,2,3-triazol-1-yl)-N-((2-methylpyrimidin-5-yl)methyl)-3-(5-methylthiazol-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiazol-2-yl)-8-(5-(trifluoromethyl)-1H-1,2,3-triazol-1-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(5-(tert-butyl)-1H-1,2,3-triazol-1-yl)-3-(5-methylthiazol-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)propyl)-8-(5-ethyl-1H-1,2,3-triazol-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(5-(difluoromethyl)-1H-1,2,3-triazol-1-yl)-3-(5-(trifluoromethyl)thiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(5-(difluoromethyl)-1H-1,2,3-triazol-1-yl)-3-(5-methylfuran-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)propyl)-8-(5-isopropyl-1H-1,2,3-triazol-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(5-ethyl-1H-1,2,3-triazol-1-yl)-3-(5-methylfuran-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-3-(5-methylthiophen-2-yl)-8-(5-propyl-1H-1,2,3-triazol-1-yl)imidazo[1,2-a]pyridine-6-carboxamide,N-((2-methylpyrimidin-5-yl)methyl)-3-(5-methylthiazol-2-yl)-8-(5-propyl-1H-1,2,3-triazol-1-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-(difluoromethyl)-1H-1,2,3-triazol-1-yl)-3-(5-methylfuran-2-yl)-N-((2-methylpyrimidin-5-yl)methyl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-(difluoromethyl)-1H-1,2,3-triazol-1-yl)-N-((2-methylpyrimidin-5-yl)methyl)-3-(2-methylthiazol-5-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)propyl)-8-(5-(tert-butyl)-1H-1,2,3-triazol-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,N-((2-methylpyrimidin-5-yl)methyl)-3-(5-methylthiazol-2-yl)-8-(5-(trifluoromethyl)-1H-1,2,3-triazol-1-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)propyl)-3-(5-chlorothiophen-2-yl)-8-(5-isopropyl-1H-1,2,3-triazol-1-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(5-(1,1-difluoroethyl)-1H-1,2,3-triazol-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-(1,1-difluoroethyl)-1H-1,2,3-triazol-1-yl)-N-((2-methylpyrimidin-5-yl)methyl)-3-(5-methylthiazol-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-(1,1-difluoroethyl)-1H-1,2,3-triazol-1-yl)-N-((2-methylpyrimidin-5-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)-8-(5-ethyl-1H-1,2,3-triazol-1-yl)-N-(2-methyl-1-(4H-1,2,4-triazol-3-yl)propyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(2-methyl-1-(4H-1,2,4-triazol-3-yl)propyl)-8-(5-methyl-1H-1,2,3-triazol-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-ethyl-1H-1,2,3-triazol-1-yl)-N-((2-methylpyrimidin-5-yl)methyl)-3-(5-methylthiazol-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-3-(5-chlorothiophen-2-yl)-8-(5-(1,1-difluoroethyl)-1H-1,2,3-triazol-1-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-(difluoromethyl)-1H-1,2,3-triazol-1-yl)-N-((5-methylpyrazin-2-yl)methyl)-3-(5-methylthiazol-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-(difluoromethyl)-1H-1,2,3-triazol-1-yl)-3-(5-methylfuran-2-yl)-N-((5-methylpyrazin-2-yl)methyl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-3-(5-chlorothiophen-2-yl)-8-(5-(trifluoromethyl)-1H-1,2,3-triazol-1-yl)imidazo[1,2-a]pyridine-6-carboxamide,N-((2-methylpyrimidin-5-yl)methyl)-3-(5-methylthiophen-2-yl)-8-(5-(2,2,2-trifluoroethyl)-1H-1,2,3-triazol-1-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-3-(5-methylthiophen-2-yl)-8-(5-(2,2,2-trifluoroethyl)-1H-1,2,3-triazol-1-yl)imidazo[1,2-a]pyridine-6-carboxamide,N-((2-methylpyrimidin-5-yl)methyl)-3-(5-methylthiazol-2-yl)-8-(5-(2,2,2-trifluoroethyl)-1H-1,2,3-triazol-1-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-(difluoromethyl)-1H-1,2,3-triazol-1-yl)-N-((6-methoxypyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(R)-8-(5-(difluoromethyl)-1H-1,2,3-triazol-1-yl)-N-(1-(2-methylpyrimidin-5-yl)ethyl)-3-(5-methylthiazol-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(R)-8-(5-(difluoromethyl)-1H-1,2,3-triazol-1-yl)-N-(1-(3-methyl-1,2,4-oxadiazol-5-yl)ethyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,N-((2-methoxypyrimidin-5-yl)methyl)-3-(5-methylthiazol-2-yl)-8-(5-(trifluoromethyl)-1H-1,2,3-triazol-1-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-(1,1-difluoroethyl)-1H-1,2,3-triazol-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiazol-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(R)-8-(5-ethyl-1H-1,2,3-triazol-1-yl)-N-(1-(3-methyl-1,2,4-oxadiazol-5-yl)ethyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,2-methyl-5-((3-(5-methylthiophen-2-yl)-8-(phenylamino)imidazo[1,2-a]pyridine-6-carboxamido)methyl)pyridine1-oxide,N-((1-methyl-2-oxo-1,2-dihydropyridin-4-yl)methyl)-3-(5-methylthiophen-2-yl)-8-(phenylamino)imidazo[1,2-a]pyridine-6-carboxamide,N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)-8-(phenylamino)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-3-(5-methylthiophen-2-yl)-8-(thiazol-2-ylamino)imidazo[1,2-a]pyridine-6-carboxamide,N-((1-methyl-2-oxo-1,2-dihydropyridin-4-yl)methyl)-3-(5-methylthiophen-2-yl)-8-(thiazol-2-ylamino)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-((5-methylthiazol-2-yl)amino)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-((4-fluorophenyl)amino)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-((2-methoxyphenyl)amino)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,2-methyl-5-((8-(1-methyl-1H-pyrazol-4-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamido)methyl)pyridine1-oxide,8-(1-methyl-1H-pyrazol-4-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(1-methyl-1H-pyrazol-4-yl)-N-((1-methyl-2-oxo-1,2-dihydropyridin-4-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(1-methyl-1H-pyrazol-5-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-3,8-bis(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,N—((S)-1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(3,5-dimethylisoxazol-4-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(1-ethyl-1H-pyrazol-5-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(1-(cyclopropylmethyl)-1H-pyrazol-4-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(1-(2-fluoroethyl)-1H-pyrazol-4-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(3,5-dimethylisoxazol-4-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,N—((S)-1-(4H-1,2,4-triazol-3-yl)ethyl)-3-(5-chlorothiophen-2-yl)-8-(3,5-dimethylisoxazol-4-yl)imidazo[1,2-a]pyridine-6-carboxamide,N—((S)-1-(4H-1,2,4-triazol-3-yl)propyl)-8-(3,5-dimethylisoxazol-4-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,N—((S)-1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(3,5-dimethylisoxazol-4-yl)-3-(5-methylthiazol-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,N—((S)-1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(3,5-dimethyl-1H-pyrazol-4-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(3,5-dimethyl-1H-pyrazol-4-yl)-N-((2-methylpyrimidin-5-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(1-(2-amino-2-oxoethyl)-1H-pyrazol-4-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(1-ethyl-1H-pyrazol-5-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,2-methyl-5-((8-(4-methylpiperidin-1-yl)-3-(propylthio)imidazo[1,2-a]pyridine-6-carboxamido)methyl)pyridine1-oxide,8-(4-methylpiperidin-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(4-methylpiperidin-1-yl)-N-((5-methylpyrazin-2-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,2-methyl-5-((8-(4-methylpiperidin-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamido)methyl)pyridine1-oxide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-3-(5-chlorothiophen-2-yl)-8-(4-methylpiperidin-1-yl)imidazo[1,2-a]pyridine-6-carboxamide,5-((3-(5-chlorothiophen-2-yl)-8-(4-methylpiperidin-1-yl)imidazo[1,2-a]pyridine-6-carboxamido)methyl)-2-methylpyridine1-oxide,5-((8-(cyclohexylamino)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamido)methyl)-2-methylpyridine1-oxide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(cyclohexylamino)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,5-((8-(4,4-dimethylpiperidin-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamido)methyl)-2-methylpyridine1-oxide,5-((8-(4,4-difluoropiperidin-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamido)methyl)-2-methylpyridine1-oxide,5-((8-(cyclohexylamino)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamido)methyl)-2-(trifluoromethyl)pyridine1-oxide,2-methyl-5-((8-(4-methylpiperidin-1-yl)-3-(5-methylthiazol-2-yl)imidazo[1,2-a]pyridine-6-carboxamido)methyl)pyridine1-oxide,5-((8-(cyclohexyl(methyl)amino)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamido)methyl)-2-methylpyridine1-oxide,5-((8-(4-fluoropiperidin-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamido)methyl)-2-methylpyridine1-oxide,N-((1-methyl-2-oxo-1,2-dihydropyridin-4-yl)methyl)-8-(4-methylpiperidin-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(4,4-dimethylpiperidin-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(4,4-difluoropiperidin-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,2-methyl-5-((3-(5-methylthiophen-2-yl)-8-(4-(trifluoromethyl)piperidin-1-yl)imidazo[1,2-a]pyridine-6-carboxamido)methyl)pyridine1-oxide,5-((8-(4-(fluoromethyl)piperidin-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamido)methyl)-2-methylpyridine1-oxide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(4-(fluoromethyl)piperidin-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-3-(5-methylthiophen-2-yl)-8-(4-(trifluoromethyl)piperidin-1-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(cyclopentylamino)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(4,4-difluoropiperidin-1-yl)-3-(4-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(4-fluoropiperidin-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,N—((S)-1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(3-methoxypyrrolidin-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(4-methoxy-4-methylpiperidin-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(4-methoxypiperidin-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,N—((S)-1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(3-methoxypiperidin-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,N—((S)-1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(3-methoxy-3-methylpyrrolidin-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(1H-pyrazol-3-yl)ethyl)-8-(4,4-difluoropiperidin-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)propyl)-8-(4,4-difluoropiperidin-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)-8-(4,4-difluoropiperidin-1-yl)-N-(2-methyl-1-(4H-1,2,4-triazol-3-yl)propyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,3-((8-(4-methylpiperidin-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamido)methyl)pyridine1-oxide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)propyl)-8-(4-methoxypiperidin-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(4-carbamoyl-4-methylpiperidin-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(1H-1,2,4-triazol-5-yl)ethyl)-8-(4-methylpiperidin-1-yl)-3-(m-tolyl)imidazo[1,2-a]pyridine-6-carboxamide,2-methyl-5-((8-(4-methylpiperidin-1-yl)-3-(o-tolyl)imidazo[1,2-a]pyridine-6-carboxamido)methyl)pyridine1-oxide,8-(5-isopropyl-1H-tetrazol-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-isopropyl-1H-tetrazol-1-yl)-3-(5-methylthiophen-2-yl)-N-((6-(trifluoromethyl)pyridin-3-yl)methyl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-ethyl-1H-tetrazol-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,N-((6-cyclopropylpyridin-3-yl)methyl)-8-(5-ethyl-1H-tetrazol-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-cyclobutyl-1H-tetrazol-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-(cyclopropylmethyl)-1H-tetrazol-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-methyl-1H-tetrazol-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)-8-(5-propyl-1H-tetrazol-1-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-isopropyl-1H-tetrazol-1-yl)-3-(5-methylthiophen-2-yl)-N-(1-(pyrazin-2-yl)ethyl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-cyclobutyl-1H-tetrazol-1-yl)-3-(5-methylthiophen-2-yl)-N-(1-(pyrazin-2-yl)ethyl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-cyclobutyl-1H-tetrazol-1-yl)-N-((1-methyl-2-oxo-1,2-dihydropyridin-4-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-ethyl-1H-tetrazol-1-yl)-3-(5-methylthiophen-2-yl)-N-(1-(pyrazin-2-yl)ethyl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-cyclobutyl-1H-tetrazol-1-yl)-N-((6-methoxypyridin-3-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-cyclobutyl-1H-tetrazol-1-yl)-N-((5-methylpyrazin-2-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(5-cyclobutyl-1H-tetrazol-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(5-(cyclopropylmethyl)-1H-tetrazol-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(5-cyclopropyl-1H-tetrazol-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(5-(difluoromethyl)-1H-tetrazol-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-(difluoromethyl)-1H-tetrazol-1-yl)-N-((2-methoxypyrimidin-5-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-3-(5-chlorothiophen-2-yl)-8-(5-(difluoromethyl)-1H-tetrazol-1-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)propyl)-8-(5-(difluoromethyl)-1H-tetrazol-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-(difluoromethyl)-1H-tetrazol-1-yl)-N-((2-methylpyrimidin-5-yl)methyl)-3-(5-methylthiazol-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-(difluoromethyl)-1H-tetrazol-1-yl)-N-((6-methylpyridin-3-yl)methyl)-3-(5-methylthiazol-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)propyl)-3-(5-chlorothiophen-2-yl)-8-(5-(difluoromethyl)-1H-tetrazol-1-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-3-(5-chlorothiophen-2-yl)-8-(5-cyclopropyl-1H-tetrazol-1-yl)imidazo[1,2-a]pyridine-6-carboxamide,3-(5-chlorothiophen-2-yl)-8-(5-(difluoromethyl)-1H-tetrazol-1-yl)-N-((2-methylpyrimidin-5-yl)methyl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-(difluoromethyl)-1H-tetrazol-1-yl)-N-((2-methylpyrimidin-5-yl)methyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(5-ethyl-1H-tetrazol-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-3-(5-methylthiophen-2-yl)-8-(5-propyl-1H-tetrazol-1-yl)imidazo[1,2-a]pyridine-6-carboxamide,(R)-8-(5-(difluoromethyl)-1H-tetrazol-1-yl)-N-(1-(5-methyl-1,3,4-oxadiazol-2-yl)ethyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-3-(5-methylthiophen-2-yl)-8-(5-(2,2,2-trifluoroethyl)-1H-tetrazol-1-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(5-(1,1-difluoroethyl)-1H-tetrazol-1-yl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-(difluoromethyl)-1H-tetrazol-1-yl)-3-(5-methylfuran-2-yl)-N-((2-methylpyrimidin-5-yl)methyl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-3-(5-chlorothiophen-2-yl)-8-(5-(1,1-difluoroethyl)-1H-tetrazol-1-yl)imidazo[1,2-a]pyridine-6-carboxamide,8-(5-(difluoromethyl)-1H-tetrazol-1-yl)-N-((5-methylpyrazin-2-yl)methyl)-3-(5-methylthiazol-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(R)-8-(5-(1,1-difluoroethyl)-1H-tetrazol-1-yl)-N-(1-(3-methyl-1,2,4-oxadiazol-5-yl)ethyl)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(N-methylpropionamido)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide,and(S)—N-(1-(4H-1,2,4-triazol-3-yl)ethyl)-8-(N-cyclopropylpropionamido)-3-(5-methylthiophen-2-yl)imidazo[1,2-a]pyridine-6-carboxamide.45. The method according to claim 1, wherein said regulating comprisesinhibition.
 46. A method for treating a respiratory dysfunction in apatient, comprising administering to the patient thereof an effectiveamount of a compound of formula (I):

or a pharmaceutically acceptable salt or prodrug thereof, wherein: R¹ isoptionally substituted heteroaryl or NR⁵R⁶; R² is optionally substitutedaryl, optionally substituted heteroaryl, C₁ to C₆ alkyl, or S—C₁ to C₆alkyl; R³ is H or C₁ to C₆ alkyl; R⁴ is optionally substitutedheteroaryl; R⁵ and R⁶ are, independently, selected from the groupconsisting of H, optionally substituted C₁ to C₆ alkyl, C₃ to C₆cycloalkyl, optionally substituted aryl, optionally substitutedheteroaryl, and CO(C₁ to C₆ alkyl); or R⁵ and R⁶ are joined to form a 5or 6-membered heterocyclic ring optionally substituted by one or more ofhalogen, C₁ to C₆ alkyl, C₁ to C₆ alkoxy, C₁ to C₆ hydroxyalkyl, C₃ toC₆ cycloalkyl, C₁ to C₆ alkyl containing 1 to 3 fluorine atoms, C₃ to C₆cycloalkyl-C₁ to C₆ alkyl, or CONH₂.
 47. The method according to claim46, wherein said respiratory dysfunction is one or more of bronchialhyperactivity, bronchoconstriction, bronchospasm, hypersecretion, cough,cough hypersensitivity syndrome, wheezing, dyspnea, breathless, andchest tightness.
 48. The method according to claim 46, wherein saidrespiratory dysfunction is caused by idiopathic pulmonary fibrosis(IPF), chronic obstructive pulmonary disease (COPD), asthma, upperrespiratory infection, interstitial lung disease (ILD), post-nasal drip,bronchitis, gastroesophageal reflux disease (GERD), treatment with anACE (Angiotensin Converting Enzyme) inhibitor, or smoking.
 49. Themethod according to claim 47, wherein said cough is acute cough,sub-acute cough, chronic cough, pathologic cough, or the urge to cough.50. The method according to claim 47, wherein said cough is caused byidiopathic pulmonary fibrosis (IPF), chronic obstructive pulmonarydisease (COPD), asthma, upper respiratory infection, interstitial lungdisease (ILD), post-nasal drip, bronchitis, gastroesophageal refluxdisease (GERD), treatment with an ACE (Angiotensin Converting Enzyme)inhibitor, or smoking.
 51. The method according to claim 46, whereinsaid administration is oral, intramuscular, rectal, cutaneous,subcutaneous, topical, transdermal, sublingual, nasal, vaginal,epidural, intrathecal, intravesical, ocular, or inhalation.
 52. Themethod according to claim 46, wherein said administration is bypressurized metered dose inhaler, nebulizer, dry powder inhaler (DPI) ornasal spray.
 53. A pharmaceutical composition useful for treating arespiratory dysfunction in a patient comprising an effective amount of acompound of formula (I):

or a pharmaceutically acceptable salt or prodrug thereof, wherein: R¹ isoptionally substituted heteroaryl or NR⁵R⁶; R² is optionally substitutedaryl, optionally substituted heteroaryl, C₁ to C₆ alkyl, or S—C₁ to C₆alkyl; R³ is H or C₁ to C₆ alkyl; R⁴ is optionally substitutedheteroaryl; R⁵ and R⁶ are, independently, selected from the groupconsisting of H, optionally substituted C₁ to C₆ alkyl, C₃ to C₆cycloalkyl, optionally substituted aryl, optionally substitutedheteroaryl, and CO(C₁ to C₆ alkyl); or R⁵ and R⁶ are joined to form a 5or 6-membered heterocyclic ring optionally substituted by one or more ofhalogen, C₁ to C₆ alkyl, C₁ to C₆ alkoxy, C₁ to C₆ hydroxyalkyl, C₃ toC₆ cycloalkyl, C₁ to C₆ alkyl containing 1 to 3 fluorine atoms, C₃ to C₆cycloalkyl-C₁ to C₆ alkyl, or CONH₂, and a pharmaceutically acceptablecarrier.